Methods for direct fabrication of dental appliances with varying feature thicknesses and associated systems

ABSTRACT

Methods and systems for digitally designing a plurality of aligners are provided. In some embodiments, a method includes receiving an intraoral scan of the patient&#39;s teeth, and generating 3D dental model of the patient&#39;s teeth using the intraoral scan. The method can include identifying a movement path to move the patient&#39;s teeth from an initial arrangement toward a target arrangement through a plurality of intermediate arrangements in accordance with a treatment plan. The method can also include identifying one or more appliance features of at least one aligner, the one or more appliance features including one or more feature regions having one or more feature thicknesses. The method can further include instructing an additive manufacturing machine to directly fabricate the at least one aligner in a layer-by-layer fashion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.18/146,153, filed Dec. 23, 2022, which is a continuation of U.S.application Ser. No. 15/202,254, filed Jul. 5, 2016, now U.S. Pat. No.11,571,278, issued Feb. 7, 2023, which claims the benefit of U.S.Provisional Application No. 62/189,291, filed Jul. 7, 2015, U.S.Provisional Application No. 62/189,312, filed Jul. 7, 2015, and U.S.Provisional Application No. 62/189,317, filed Jul. 7, 2015, thedisclosures of each of which are incorporated herein by reference intheir entirety.

The subject matter of the following co-pending patent applications isrelated to the present application: U.S. application Ser. No.15/202,342, filed Jul. 5, 2016, entitled “ORTHODONTIC ALIGNERS USINGMULTIPLE MATERIALS”, which claims the benefit of U.S. ProvisionalApplication No. 62/189,259, filed Jul. 7, 2015 and U.S. ProvisionalApplication No. 62/189,282, filed Jul. 7, 2015; U.S. application Ser.No. 15/202,472, filed Jul. 5, 2016, entitled “DIRECT FABRICATION OFALIGNERS WITH INTERPROXIMAL FORCE COUPLING”, which claims the benefit ofU.S. Provisional Application No. 62/189,263, filed Jul. 7, 2015; U.S.application Ser. No. 15/202,452, filed Jul. 5, 2016, entitled “DIRECTFABRICATION OF ALIGNERS FOR ARCH EXPANSION”, which claims the benefit ofU.S. Provisional Application No. 62/189,271, filed Jul. 7, 2015, andU.S. Provisional Application No. 62/189,301, filed Jul. 7, 2015; U.S.application Ser. No. 15/202,348, filed Jul. 5, 2016, entitled “DIRECTFABRICATION OF ATTACHMENT TEMPLATES WITH ADHESIVE”, which claimed thebenefit of U.S. Provisional Application No. 62/189,259, filed Jul. 7,2015, and U.S. Provisional Application No. 62/189,282, filed Jul. 7,2015; U.S. application Ser. No. 15/202,467, filed Jul. 5, 2016, entitled“DIRECT FABRICATION CROSS-LINKING FOR PALATE EXPANSION AND OTHERAPPLICATIONS”, which claims the benefit of U.S. Provisional ApplicationNo. 62/189,301, filed Jul. 7, 2015, and U.S. Provisional Application No.62/189,271, filed Jul. 7, 2015; U.S. application Ser. No. 15/202,299,filed Jul. 5, 2016, entitled “DIRECT FABRICATION OF POWER ARMS”, whichclaims the benefit of U.S. Provisional Application No. 62/189,291, filedJul. 7, 2015, U.S. Provisional Application No. 62/189,312, filed Jul. 7,2015, and U.S. Provisional Application No. 62/189,317, filed Jul. 7,2015; U.S. application Ser. No. 15/202,187, filed Jul. 5, 2016, entitled“DIRECT FABRICATION OF ORTHODONTIC APPLIANCES WITH VARIABLE PROPERTIES”,which claims the benefit of U.S. Provisional Application No. 62/189,291,filed Jul. 7, 2015, U.S. Provisional Application No. 62/189,312, filedJul. 7, 2015, and U.S. Provisional Application No. 62/189,317, filedJul. 7, 2015; U.S. application Ser. No. 15/202,139, filed Jul. 5, 2016,entitled “SYSTEMS, APPARATUSES AND METHODS FOR SUBSTANCE DELIVERY FROMDENTAL APPLIANCE”, which claims the benefit of U.S. ProvisionalApplication No. 62/189,303, filed Jul. 7, 2015; U.S. Application Ser.No. 62/189,303, filed Jul. 5, 2016, entitled “DENTAL MATERIALS USINGTHERMOSET POLYMERS”, which claims the benefit of U.S. ProvisionalApplication No. 62/189,380, filed Jul. 7, 2015; and U.S. applicationSer. No. 15/202,083, filed Jul. 5, 2016, entitled “DENTAL APPLIANCEHAVING ORNAMENTAL DESIGN”, which claims the benefit of U.S. ProvisionalApplication No. 62/189,318, filed Jul. 7, 2015, the entire disclosuresof which are incorporated herein by reference.

BACKGROUND

Prior orthodontic procedures typically involve repositioning a patient'steeth to a desired arrangement in order to correct malocclusions and/orimprove aesthetics. To achieve these objectives, orthodontic appliancessuch as braces, retainers, shell aligners, and the like can be appliedto the patient's teeth by an orthodontic practitioner. The appliance canbe configured to exert force on one or more teeth in order to effectdesired tooth movements. The application of force can be periodicallyadjusted by the practitioner (e.g., by altering the appliance or usingdifferent types of appliances) in order to incrementally reposition theteeth to a desired arrangement.

The prior orthodontic methods and apparatus to move teeth can be lessthan ideal in at least some respects. In some instances, priororthodontic approaches that employ an appliance with homogeneous and/orcontinuous material properties may not provide sufficient control overthe forces applied to the teeth. In some instances, prior orthodontictreatment involves using a repositioning appliance in combination with asupplementary device that is fabricated separately. In some instances,although prior power arms can be used to apply torque to teeth, the useand placement of power arms can be less than ideal.

In light of the above, improved orthodontic appliances are needed.Ideally such appliances would provide more accurate tooth movement withimproved control over the forces applied to the teeth.

SUMMARY

Improved systems, methods, and devices for repositioning a patient'steeth are provided herein. An orthodontic appliance for repositioningteeth can comprise variable localized properties in order to improvecontrol of force and/or torque application onto different subsets ofteeth. In some embodiments, an orthodontic appliance comprises aheterogeneous thickness, stiffness, and/or material composition acrossdifferent portions of the appliance in order to provide more precisecontrol over the forces applied to the teeth. An appliance with aheterogeneous thickness, stiffness, and/or material composition can beproduced by direct fabrication techniques which provide control of theappliance geometry and material composition in three dimensions. Thedirect fabrication methods herein allow for the production of applianceswith complex and heterogeneous appliance geometries and compositionsthat would otherwise be difficult to achieve using prior fabricationmethods.

Systems, methods, and devices for orthodontic appliances with integrallyformed features are provided herein. An orthodontic appliance withintegrally formed features can include an appliance shell adapted to beworn over one or more teeth and a feature integrally formed into theappliance, e.g., by direct fabrication. Advantages of the system,methods and devices described herein include one or more of thefollowing: (1) the appliance and feature are produced in a singlefabrication step such that the feature is integrally formed into theappliance; (2) use of direct fabrication allows for integrally formedfeatures with geometries that are otherwise complicated, cumbersome, andoften precluded by previous indirect fabrication technologies; and (3)appliances directly fabricated with integrally formed features may allowfor more flexible and convenient orthodontic treatment.

Systems, methods, and devices for improved power arms for moving teethare provided herein. The power arms can be directly fabricated with anappliance to move teeth in order to provide additional amounts of forceto the teeth with the appliance. Alternatively, the power arms maycomprise attachment structures to adhere the power arms to the teeth.The power arms can be directly fabricated with a connecting springstructure extending between the power arms. The connecting springstructure can be directly fabricated to generate predetermined amountsof force when placed on the teeth to provide improved tooth movement.The power arms can be directly fabricated with a three dimensional shapeprofile determined in response to a scan of the mouth of the patient, inorder to improve comfort. The power arms can be directly fabricated withalignment structures shaped to receive features of the teeth in order toaccurately place the power arms accurately on the teeth. The power armscan be directly fabricated with a preloaded connecting structureextending between the power arms to apply force to the power arms, and acounter-force connector extending between the power arms to oppose thepreloaded connecting structure and facilitate placement.

In another aspect, a method for fabricating an orthodontic appliancecomprising an integrally formed component is provided. The method cancomprise: determining a movement path to move one or more teeth from aninitial arrangement to a target arrangement; determining an appliancegeometry for an orthodontic appliance comprising a shell and anintegrally formed component, wherein the shell comprises a plurality ofteeth receiving cavities shaped to move the one or more teeth from theinitial arrangement to the target arrangement; and generatinginstructions for direct fabrication of the orthodontic appliance,wherein the instructions are configured to cause direct fabrication ofthe shell using a first material and direct fabrication of theintegrally formed component using a second, different material.

In another aspect, a system for fabricating an orthodontic appliancecomprising an integrally formed component is provided. The system cancomprise one or more processors configured with instructions to:determine a movement path to move one or more teeth from an initialarrangement to a target arrangement; determine an appliance geometry foran orthodontic appliance comprising a shell and an integrally formedcomponent, wherein the shell comprises a plurality of teeth receivingcavities shaped to move the one or more teeth from the initialarrangement to the target arrangement; and generate instructions fordirect fabrication of the orthodontic appliance, wherein theinstructions are configured to cause direct fabrication of the shellusing a first material and direct fabrication of the integrally formedcomponent using a second, different material.

In another aspect, an appliance for placement on teeth of a patient isprovided. The appliance comprises: a plurality of power arms; aconnecting structure coupled to the plurality of power arms to apply afirst force to the plurality of power arms; and a counter-forceconnector coupled to the plurality of power arms to apply a second forceto the plurality of power arms opposing the first force.

In another aspect, a method of fabricating an orthodontic appliance isprovided. The method comprises: determining a movement path to move oneor more teeth from an initial arrangement to a target arrangement;determining an appliance geometry for an orthodontic applianceconfigured to produce movement of the one or more teeth from the initialarrangement to the target arrangement, the orthodontic appliancecomprising a plurality of power arms; and generating instructions fordirect fabrication of the orthodontic appliance comprising the pluralityof power arms.

Other objects and features of the present invention will become apparentby a review of the specification, claims, and appended figures.

INCORPORATION BY REFERENCE

All publications, patents, and patent applications mentioned in thisspecification are herein incorporated by reference to the same extent asif each individual publication, patent, or patent application wasspecifically and individually indicated to be incorporated by reference.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention are set forth with particularity inthe appended claims. A better understanding of the features andadvantages of the present invention will be obtained by reference to thefollowing detailed description that sets forth illustrative embodiments,in which the principles of the invention are utilized, and theaccompanying drawings of which:

FIG. 1A illustrates a tooth repositioning appliance, in accordance withembodiments;

FIG. 1B illustrates a tooth repositioning system, in accordance withembodiments;

FIG. 1C illustrates a method of orthodontic treatment using a pluralityof appliances, in accordance with embodiments;

FIGS. 2A and 2B illustrate orthodontic appliances with varying occlusalthicknesses, in accordance with embodiments;

FIGS. 3A and 3B illustrate orthodontic appliances with varyingthicknesses along a vertical direction, in accordance with embodiments;

FIG. 4A shows a cross-sectional view of an exemplary force applicationstructure, in accordance with embodiments;

FIG. 4B shows a cross-sectional view of another exemplary forceapplication structure, in accordance with embodiments;

FIG. 4C shows a cross-sectional view of an appliance shell with forceapplication structures for controlling tooth tipping and/or torque, inaccordance with embodiments;

FIG. 4D shows a cross-sectional view of an appliance shell with forceapplication structures for controlling tooth root movements, inaccordance with embodiments;

FIG. 4E shows a cross-sectional occlusal view of an appliance shell withforce application structures for controlling tooth rotation, inaccordance with embodiments;

FIG. 5A illustrates an appliance with built-in handle structures in theappliance shell, in accordance with embodiments;

FIGS. 5B through 5D illustrate exemplary geometries for handlestructures, in accordance with embodiments;

FIG. 6 illustrates a cross-sectional view of an appliance shell withgingival edges shaped to improve patient comfort, in accordance withembodiments;

FIG. 7 illustrates an appliance with one or more thickened ribs forincreased stiffness, in accordance with embodiments;

FIG. 8 illustrates an appliance with a plurality of thinner regions forreduced stiffness, in accordance with embodiments;

FIG. 9 shows a cross-sectional view of an appliance shell with varyingdegrees of photopolymerization, in accordance with embodiments;

FIG. 10 shows a cross-sectional view of an appliance shell configuredfor tooth rotation, in accordance with embodiments;

FIG. 11A illustrates an appliance with a plurality of force isolatedsegments, in accordance with embodiments;

FIG. 11B illustrates an appliance configured for force transfer betweena plurality of force isolated segments, in accordance with embodiments;

FIG. 11C illustrates an exemplary force transfer configuration, inaccordance with embodiments;

FIG. 11D illustrates another exemplary force transfer configuration, inaccordance with embodiments;

FIG. 11E illustrates an appliance with a plurality of segments used incombination with an elastic, in accordance with embodiments;

FIG. 11F illustrates an appliance with a plurality of segments used incombination with an elastic, in accordance with embodiments;

FIG. 12A illustrates an appliance with different materials used for theocclusal portion and gingival portion, in accordance with embodiments;

FIG. 12B illustrates an appliance with different materials used for thebuccal portion and lingual portion, in accordance with embodiments;

FIG. 13 illustrates an appliance with variable stiffness along differentdirections for uprighting a tooth, in accordance with embodiments;

FIGS. 14A through 14C illustrate use of anisotropic properties forreducing unwanted pairing of movements, in accordance with embodiments;

FIG. 15 illustrates a tooth repositioning system, in accordance withembodiments;

FIG. 16 illustrates an orthodontic appliance with an integrally formedreinforcing structure, in accordance with embodiments;

FIG. 17 illustrates an orthodontic appliance with integrally formedhollow portions, in accordance with embodiments;

FIG. 18 illustrates an orthodontic appliance with an integrally formedocclusal block, in accordance with embodiments;

FIG. 19 illustrates an orthodontic appliance with an integrally formedarch expander, in accordance with embodiments;

FIG. 20 illustrates an orthodontic appliance with an integrally formedair flow structure, in accordance with embodiments;

FIG. 21 illustrates an orthodontic appliance with an integrally formedpontic, in accordance with embodiments.

FIG. 22 illustrates an orthodontic appliance with an integrally formedcomponent that couples to another portion of the appliance, inaccordance with embodiments;

FIG. 23 illustrates an orthodontic appliance with an integrally formedcomponent that couples to an appliance worn on the opposing jaw, inaccordance with embodiments;

FIG. 24 illustrates an orthodontic appliance with an integrally formedcomponent that couples to a device coupled to an intraoral structure, inaccordance with embodiments.

FIG. 25 illustrates an orthodontic appliance with integrally formedmounting features for coupling an elastic, in accordance withembodiments;

FIG. 26 illustrates an orthodontic system including an upper appliancewith an integrally formed upper mounting feature and a lower appliancewith an integrally formed lower mounting feature for coupling anelastic, in accordance with embodiments;

FIG. 27 illustrates an orthodontic appliance including a cutoutaccommodating a coupled elastic, in accordance with embodiments;

FIG. 28 illustrates an orthodontic appliance including a cutout foraccommodating a coupled elastic, in accordance with embodiments

FIG. 29 illustrates an orthodontic appliance including integrally formedmounting features for coupling a spring, in accordance with embodiments;

FIG. 30 illustrates an orthodontic appliance including integrally formedmounting features for coupling an advancement structure, in accordancewith embodiments;

FIG. 31 illustrates an orthodontic appliance comprising a pair ofdirectly fabricated power arms, in accordance with embodiments;

FIG. 32 illustrates a patient's mouth, in which a directly fabricatedpower arm is coupled to a tooth to apply a tooth-moving force, inaccordance with embodiments;

FIGS. 33A through 33C illustrates various spring structures that may befabricated as part of a power arm structure, in accordance withembodiments;

FIG. 34 illustrates a “pre-loading” mechanism whereby the power arm'stooth-moving force is balanced for easier placement on a patient'steeth, in accordance with embodiments;

FIGS. 35A through 35C illustrates the operation of a counter-forceconnecter to pre-load a pair of power arms for installation, inaccordance with embodiments;

FIGS. 36A through 36C illustrates the operation of a counter-forceconnecter to pre-load a pair of power arms for installation, inaccordance with embodiments;

FIGS. 37A through 37D illustrate single power arm appliances, inaccordance with embodiments;

FIG. 38 illustrates a method for designing an orthodontic appliance, inaccordance with embodiments;

FIG. 39 illustrates a method for digitally planning an orthodontictreatment, in accordance with embodiments; and

FIG. 40 is a simplified block diagram of a data processing system, inaccordance with embodiments.

DETAILED DESCRIPTION

A better understanding of the features and advantages of the presentdisclosure will be obtained by reference to the following detaileddescription that sets forth illustrative embodiments, in which theprinciples of embodiments of the present disclosure are utilized, andthe accompanying drawings.

Although the detailed description contains many specifics, these shouldnot be construed as limiting the scope of the disclosure but merely asillustrating different examples and aspects of the present disclosure.It should be appreciated that the scope of the disclosure includes otherembodiments not discussed in detail above. Various other modifications,changes and variations which will be apparent to those skilled in theart may be made in the arrangement, operation and details of themethods, systems, and apparatus of the present disclosure providedherein without departing from the spirit and scope of the invention asdescribed herein.

As used herein the terms “dental appliance,” “orthodontic appliance,”and “tooth receiving appliance” are treated synonymously.

As used herein the terms “rigid” and “stiff” are treated synonymously.

As used herein the term “and/or” is used as a functional word toindicate that two words or expressions are to be taken together orindividually. For example, A and/or B encompasses A alone, B alone, andA and B together.

As used herein the terms “torque” and “moment” are treated synonymously.

As used herein a “moment” encompasses a force acting on an object suchas a tooth at a distance from a center of resistance. The moment may becalculated with a vector cross product of a vector force applied to alocation corresponding to a displacement vector from the center ofresistance, for example. The moment may comprise a vector pointing in adirection. A moment opposing another moment may encompass one of themoment vectors oriented toward a first side of the object such as thetooth and the other moment vector oriented toward an opposite side ofthe object such as tooth, for example. Any discussion herein referringto application of forces on a patient's teeth is equally applicable toapplication of moments on the teeth, and vice-versa.

As used herein a “plurality of teeth” encompasses two or more teeth. Insome embodiments, one or more posterior teeth comprises one or more of amolar, a premolar or a canine, and one or more anterior teeth comprisingone or more of a central incisor, a lateral incisor, a cuspid, a firstbicuspid or a second bicuspid.

The present disclosure provides orthodontic systems and related methodsfor designing and providing improved or more effective tooth movingsystems for eliciting a desired tooth movement and/or repositioningteeth into a desired arrangement.

The embodiments disclosed herein can be used to couple groups of one ormore teeth to each other. The groups of one or more teeth may comprise afirst group of one or more anterior teeth and a second group of one ormore posterior teeth. The first group of teeth can be coupled to thesecond group of teeth with the polymeric shell appliances as disclosedherein.

The embodiments disclosed herein are well suited for moving one or moreteeth of the first group of one or more teeth or moving one or more ofthe second group of one or more teeth, and combinations thereof.

The embodiments disclosed herein are well suited for combination withone or known commercially available tooth moving components such asattachments and polymeric shell appliances. In some embodiments, theappliance and one or more attachments are configured to move one or moreteeth along a tooth movement vector comprising six degrees of freedom,in which three degrees of freedom are rotational and three degrees offreedom are translation.

The present disclosure provides orthodontic appliances and relatedsystems, methods, and devices. Repositioning of teeth may beaccomplished with the use of a series of removable elastic positioningappliances such as the Invisalign® system available from AlignTechnology, Inc., the assignee of the present disclosure. Suchappliances may have a thin shell of elastic material that generallyconforms to a patient's teeth but is slightly out of alignment with aninitial or immediately prior tooth configuration. Placement of theappliance over the teeth applies controlled forces in specific locationsto gradually move the teeth into the new configuration. Repetition ofthis process with successive appliances comprising new configurationseventually moves the teeth through a series of intermediateconfigurations or alignment patterns to a final desired configuration.

The force generating components disclosed herein can generate forcesbased on a target tooth displacement or orientation. For example, anamount of tooth displacement can be selected, and the force generatingcomponent can be fabricated such that a tooth displacement force isgenerated when the appliance is worn, so long as the amount of toothdisplacement is less than the target tooth displacement. Thus, anappliance can generate tooth displacement forces without causingexcessive tooth displacement. In some cases, the target toothdisplacement can be adjustable; for example, adjustable screws, springs,bands, or other components can be adjusted to change the size of thealigner, thereby changing the target tooth displacement. An adjustablealigner can be used to generate a slow tooth displacement, for example.

Although reference is made to an appliance comprising a polymeric shellappliance, the embodiments disclosed herein are well suited for use withmany appliances that receive teeth, for example appliances without oneor more of polymers or shells. The appliance can be fabricated with oneor more of many materials such as metal, glass, reinforced fibers,carbon fiber, composites, reinforced composites, aluminum, biologicalmaterials, and combinations thereof for example. The appliance can beshaped in many ways, such as with thermoforming or direct fabrication asdescribed herein, for example. Alternatively or in combination, theappliance can be fabricated with machining such as an appliancefabricated from a block of material with computer numeric controlmachining.

Turning now to the drawings, in which like numbers designate likeelements in the various figures, FIG. 1A illustrates an exemplary toothrepositioning appliance or aligner 100 that can be worn by a patient inorder to achieve an incremental repositioning of individual teeth 102 inthe jaw. The appliance can include a shell (e.g., a continuous polymericshell or a segmented shell) having teeth-receiving cavities that receiveand resiliently reposition the teeth. An appliance or portion(s) thereofmay be indirectly fabricated using a physical model of teeth. Forexample, an appliance (e.g., polymeric appliance) can be formed using aphysical model of teeth and a sheet of suitable layers of polymericmaterial. In some embodiments, a physical appliance is directlyfabricated, e.g., using additive manufacturing techniques, from adigital model of an appliance. An appliance can fit over all teethpresent in an upper or lower jaw, or less than all of the teeth. Theappliance can be designed specifically to accommodate the teeth of thepatient (e.g., the topography of the tooth-receiving cavities matchesthe topography of the patient's teeth), and may be fabricated based onpositive or negative models of the patient's teeth generated byimpression, scanning, and the like. Alternatively, the appliance can bea generic appliance configured to receive the teeth, but not necessarilyshaped to match the topography of the patient's teeth. In some cases,only certain teeth received by an appliance will be repositioned by theappliance while other teeth can provide a base or anchor region forholding the appliance in place as it applies force against the tooth orteeth targeted for repositioning. In some cases, some or most, and evenall, of the teeth will be repositioned at some point during treatment.Teeth that are moved can also serve as a base or anchor for holding theappliance as it is worn by the patient. Typically, no wires or othermeans will be provided for holding an appliance in place over the teeth.In some cases, however, it may be desirable or necessary to provideindividual attachments or other anchoring elements 104 on teeth 102 withcorresponding receptacles or apertures 106 in the appliance 100 so thatthe appliance can apply a selected force on the tooth. Exemplaryappliances, including those utilized in the Invisalign® System, aredescribed in numerous patents and patent applications assigned to AlignTechnology, Inc. including, for example, in U.S. Pat. Nos. 6,450,807,and 5,975,893, as well as on the company's website, which is accessibleon the World Wide Web (see, e.g., the url “invisalign.com”). Examples oftooth-mounted attachments suitable for use with orthodontic appliancesare also described in patents and patent applications assigned to AlignTechnology, Inc., including, for example, U.S. Pat. Nos. 6,309,215 and6,830,450.

Optionally, in cases involving more complex movements or treatmentplans, it may be beneficial to utilize auxiliary components (e.g.,features, accessories, structures, devices, components, and the like) inconjunction with an orthodontic appliance. Examples of such accessoriesinclude but are not limited to elastics, wires, springs, bars, archexpanders, palatal expanders, twin blocks, occlusal blocks, bite ramps,mandibular advancement splints, bite plates, pontics, hooks, brackets,headgear tubes, springs, bumper tubes, palatal bars, frameworks,pin-and-tube apparatuses, buccal shields, buccinator bows, wire shields,lingual flanges and pads, lip pads or bumpers, protrusions, divots, andthe like. In some embodiments, the appliances, systems and methodsdescribed herein include improved orthodontic appliances with integrallyformed features that are shaped to couple to such auxiliary components,or that replace such auxiliary components.

FIG. 1B illustrates a tooth repositioning system 110 including aplurality of appliances 112, 114, 116. Any of the appliances describedherein can be designed and/or provided as part of a set of a pluralityof appliances used in a tooth repositioning system. Each appliance maybe configured so a tooth-receiving cavity has a geometry correspondingto an intermediate or final tooth arrangement intended for theappliance. The patient's teeth can be progressively repositioned from aninitial tooth arrangement to a target tooth arrangement by placing aseries of incremental position adjustment appliances over the patient'steeth. For example, the tooth repositioning system 110 can include afirst appliance 112 corresponding to an initial tooth arrangement, oneor more intermediate appliances 114 corresponding to one or moreintermediate arrangements, and a final appliance 116 corresponding to atarget arrangement. A target tooth arrangement can be a planned finaltooth arrangement selected for the patient's teeth at the end of allplanned orthodontic treatment. Alternatively, a target arrangement canbe one of some intermediate arrangements for the patient's teeth duringthe course of orthodontic treatment, which may include various differenttreatment scenarios, including, but not limited to, instances wheresurgery is recommended, where interproximal reduction (IPR) isappropriate, where a progress check is scheduled, where anchor placementis best, where palatal expansion is desirable, where restorativedentistry is involved (e.g., inlays, onlays, crowns, bridges, implants,veneers, and the like), etc. As such, it is understood that a targettooth arrangement can be any planned resulting arrangement for thepatient's teeth that follows one or more incremental repositioningstages. Likewise, an initial tooth arrangement can be any initialarrangement for the patient's teeth that is followed by one or moreincremental repositioning stages.

FIG. 1C illustrates a method 150 of orthodontic treatment using aplurality of appliances, in accordance with embodiments. The method 150can be practiced using any of the appliances or appliance sets describedherein. In step 160, a first orthodontic appliance is applied to apatient's teeth in order to reposition the teeth from a first tootharrangement to a second tooth arrangement. In step 170, a secondorthodontic appliance is applied to the patient's teeth in order toreposition the teeth from the second tooth arrangement to a third tootharrangement. The method 150 can be repeated as necessary using anysuitable number and combination of sequential appliances in order toincrementally reposition the patient's teeth from an initial arrangementto a target arrangement. The appliances can be generated all at the samestage or in sets or batches (e.g., at the beginning of a stage of thetreatment), or the appliances can be fabricated one at a time, and thepatient can wear each appliance until the pressure of each appliance onthe teeth can no longer be felt or until the maximum amount of expressedtooth movement for that given stage has been achieved. A plurality ofdifferent appliances (e.g., a set) can be designed and even fabricatedprior to the patient wearing any appliance of the plurality. Afterwearing an appliance for an appropriate period of time, the patient canreplace the current appliance with the next appliance in the seriesuntil no more appliances remain. The appliances are generally notaffixed to the teeth and the patient may place and replace theappliances at any time during the procedure (e.g., patient-removableappliances). The final appliance or several appliances in the series mayhave a geometry or geometries selected to overcorrect the tootharrangement. For instance, one or more appliances may have a geometrythat would (if fully achieved) move individual teeth beyond the tootharrangement that has been selected as the “final.” Such over-correctionmay be desirable in order to offset potential relapse after therepositioning method has been terminated (e.g., permit movement ofindividual teeth back toward their pre-corrected positions).Over-correction may also be beneficial to speed the rate of correction(e.g., an appliance with a geometry that is positioned beyond a desiredintermediate or final position may shift the individual teeth toward theposition at a greater rate). In such cases, the use of an appliance canbe terminated before the teeth reach the positions defined by theappliance. Furthermore, over-correction may be deliberately applied inorder to compensate for any inaccuracies or limitations of theappliance.

Orthodontic Appliances with Variable Properties

Systems, methods, and devices for improved orthodontic treatment of apatient's teeth are provided herein. In some embodiments, the presentdisclosure provides improved orthodontic appliances having differentportions with different properties. The use of appliances with variablelocalized properties as described herein can improve control over theapplication of forces to different subsets of teeth, thus enhancing theflexibility and effectiveness of orthodontic treatment. In someembodiments, the appliances with variable localized properties hereinare produced using direct fabrication methods which provide precisecontrol over the geometry, composition, and/or properties of theappliance in three dimensions. Direct fabrication permits manufacturingof appliances with complex geometries and heterogeneous properties thatwould otherwise be difficult to produce using other fabricationtechniques.

In one aspect, an orthodontic appliance for treating a patient's teethis provided, the appliance comprising: a first appliance portionreceiving a first subset of the patient's teeth; and a second applianceportion receiving a second subset of the patient's teeth, wherein thefirst and second appliance portions differ from each other with respectto two or more of thickness, stiffness, or material composition.

In some embodiments, the first appliance portion comprises an increasedthickness relative to the second appliance portion. The first applianceportion can comprise an anterior occlusal portion and the secondappliance portion can comprise a posterior occlusal portion, or thefirst appliance portion can comprise a posterior occlusal portion andthe second appliance portion can comprise an anterior occlusal portion.The first appliance portion can comprise a gingival portion shaped toengage undercuts of teeth and the second appliance portion can comprisean occlusal portion shaped to receive crowns of teeth.

In some embodiments, the first appliance portion comprises a forceapplication structure arranged to engage and apply force to a tooth. Thefirst appliance portion can comprise a handle structure to facilitateremoval of the appliance from the patient's teeth. The first applianceportion can comprise a rib structure on a buccal surface of theappliance (e.g., near canine teeth of the patient), on an occlusalsurface of the appliance, on a lingual surface of the appliance, or on agingival portion of the appliance.

In some embodiments, the second appliance portion comprises recesses orapertures shaped to reduce stiffness of the second appliance portionrelative to the first appliance portion.

In some embodiments, the first appliance portion comprises an increasedstiffness relative to the second appliance portion. The first applianceportion can comprise an increased degree of photopolymerization relativeto the second appliance portion so as to produce the increasedstiffness. The first appliance portion can comprise a gingival portionand the second appliance portion can comprise an occlusal portion. Thefirst appliance portion can comprise a buccal portion and the secondappliance portion can comprise a lingual portion.

In some embodiments, the first appliance portion comprises a stiff bandextending along a buccal and/or lingual surface of a tooth.

In some embodiments, the first appliance portion comprises a pluralityof shell segments and the second appliance portion comprises an elasticportion joining the plurality of shell segments.

In some embodiments, the first appliance portion comprises a firstmaterial and the second appliance portion comprises a second materialdifferent from the first material. At least one of the first or secondmaterials can comprise a stiffness along a first direction differentfrom a stiffness along a second direction. The first direction can be atransverse direction and the second direction can be a verticaldirection, or the first direction can be a rotational direction and thesecond direction can be a vertical direction.

In some embodiments, the first appliance portion or the second applianceportion comprises an occlusal structure, an arch expander, an elastic,an air flow structure, a pontic, ornamental feature, inflatablestructure, or functional layer or coating.

In some embodiments, the first appliance portion is integrally formedwith the second appliance portion as a single piece using a directfabrication technique. The direct fabrication technique can be anadditive manufacturing technique or a subtractive manufacturingtechnique. The additive manufacturing technique can comprise one or moreof: vat photopolymerization, material jetting, binder jetting, materialextrusion, powder bed fusion, sheet lamination, or directed energydeposition.

In some embodiments, the appliance further comprises a third applianceportion receiving a third subset of the patient's teeth, the thirdappliance portion differing from one or more of the first and secondappliance portions with respect to two or more of thickness, stiffness,or material composition.

In another aspect, a method for treating a patient's teeth comprisesproviding an appliance as in any of the embodiments herein.

In another aspect, a method for fabricating an orthodontic appliance fortreating a patient's teeth is provided, the method comprising:determining a movement path to move one or more teeth from an initialarrangement to a target arrangement; determining a force system to movethe one or more teeth along the movement path; determining an appliancegeometry and material composition of an appliance configured to producethe force system, wherein the appliance comprises two or more of aheterogeneous thickness, a heterogeneous stiffness, or a heterogeneousmaterial composition; and generating instructions for fabricating theappliance with the appliance geometry and the material composition usinga direct fabrication technique.

In some embodiments, the direct fabrication technique is an additivemanufacturing technique or a subtractive manufacturing technique. Theadditive manufacturing technique can comprise one or more of: vatphotopolymerization, material jetting, binder jetting, materialextrusion, powder bed fusion, sheet lamination, or directed energydeposition.

In some embodiments, the appliance comprises the heterogeneousthickness, and thicker portions of the appliance are configured to exerta different force (e.g., more or less force) on the one or more teeththan thinner portions of the appliance. The method can further comprisedetermining locations and geometries for the thicker portions and thethinner portions.

In some embodiments, the appliance comprises the heterogeneousstiffness, and stiffer portions of the appliance are configured to exerta different force (e.g., more or less force) on the one or more teeththan more elastic portions of the appliance. The method can furthercomprise determining locations and geometries for the stiffer portionsand the more elastic portions. The stiffer portions can comprise adifferent material composition than the more elastic portions. Thestiffer portions can comprise a different degree of photopolymerizationthan the more elastic portions.

In some embodiments, the appliance comprises an increased stiffnessalong a targeted tooth movement direction and a decreased stiffness awayfrom the targeted tooth movement direction.

In some embodiments, the appliance comprises a plurality of relativelystiff segments joined to each other by one or more relatively elasticportions so as to isolate the forces generated by the plurality ofrelatively stiff segments from each other.

In some embodiments, the appliance further comprises one or more of: aheterogeneous elastic modulus, a heterogeneous hardness, a heterogeneousstrength, a heterogeneous compressibility, a heterogeneous stressrelaxation, a heterogeneous hydrophobicity, a heterogeneoushydrophilicity, a heterogeneous Poisson ratio, a heterogeneous strainrate, a heterogeneous viscoelasticity, or a heterogeneous polarity.

In another aspect, a system for fabricating an orthodontic appliance fortreating a patient's teeth is provided. The system can comprise one ormore processors configured with instructions to: determine a movementpath to move one or more teeth from an initial arrangement to a targetarrangement; determine a force system to move the one or more teethalong the movement path; determine an appliance geometry and materialcomposition of an appliance configured to produce the force system,wherein the appliance comprises two or more of a heterogeneousthickness, a heterogeneous stiffness, or a heterogeneous materialcomposition; and generate instructions for fabricating the appliancewith the appliance geometry and the material composition using a directfabrication technique.

In some embodiments, the direct fabrication technique is an additivemanufacturing technique or a subtractive manufacturing technique. Theadditive manufacturing technique can comprise one or more of: vatphotopolymerization, material jetting, binder jetting, materialextrusion, powder bed fusion, sheet lamination, or directed energydeposition.

In some embodiments, the appliance comprises the heterogeneousthickness, and thicker portions of the appliance are configured to exerta different force on the one or more teeth than thinner portions of theappliance.

In some embodiments, the one or more processors are further configuredwith instructions to determine locations and geometries for the thickerportions and the thinner portions.

In some embodiments, the appliance comprises the heterogeneousstiffness, and stiffer portions of the appliance are configured to exerta different force on the one or more teeth than more elastic portions ofthe appliance.

In some embodiments, the one or more processors are further configuredwith instructions to determine locations and geometries for the stifferportions and the more elastic portions.

In some embodiments, the stiffer portions comprise a different materialcomposition than the more elastic portions.

In some embodiments, the stiffer portions comprise a different degree ofphotopolymerization than the more elastic portions.

In some embodiments, the appliance comprises an increased stiffnessalong a targeted tooth movement direction and a decreased stiffness awayfrom the targeted tooth movement direction.

In some embodiments, the appliance comprises a plurality of relativelystiff segments joined to each other by one or more relatively elasticportions so as to isolate the forces generated by the plurality ofrelatively stiff segments from each other.

In some embodiments, the appliance further comprises one or more of: aheterogeneous elastic modulus, a heterogeneous hardness, a heterogeneousstrength, a heterogeneous compressibility, a heterogeneous stressrelaxation, a heterogeneous hydrophobicity, a heterogeneoushydrophilicity, a heterogeneous Poisson ratio, a heterogeneous strainrate, a heterogeneous viscoelasticity, or a heterogeneous polarity.

In another aspect, a system configured to perform any embodiment of themethods herein is provided.

The ability of an orthodontic appliance to effectively treat a patient'steeth can depend on its properties, such as stiffness, elastic modulus,hardness, thickness, strength, compressibility, stress relaxation,hydrophobicity/hydrophilicity, Poisson ratio, strain rate,viscoelasticity, and/or polarity. For instance, these properties caninfluence the amount of force and/or torque that can be exerted by theappliance onto the teeth, as well as the extent to which such forcesand/or torques can be controlled (e.g., with respect to location ofapplication, direction, magnitude, etc.). The optimal properties fortooth repositioning may vary based on the type of tooth to berepositioned (e.g., molar, premolar, canine, incisor), movement type(e.g., extrusion, intrusion, rotation, torqueing, tipping, translating),targeted movement distance, use of tooth-mounted attachments, orcombinations thereof. Different teeth in the patient's jaw may requiredifferent types of appliance properties in order to be effectivelyrepositioned. In some instances, it can be relatively difficult toeffectively reposition multiple teeth using an orthodontic appliancewith uniform and/or homogeneous properties.

Accordingly, various embodiments of the present disclosure provideorthodontic appliances having properties that are heterogeneous and/orvariable across different portions of appliance in order to allow formore effective repositioning of multiple teeth. In such embodiments, oneor more portions of the appliance can have one or more properties thatdiffer from those of one or more other portions, such as with respect toone or more of stiffness, elastic modulus, hardness, thickness,strength, compressibility, stress relaxation,hydrophobicity/hydrophilicity, Poisson ratio, strain rate,viscoelasticity, and/or polarity. An appliance can include any number ofportions with different properties, such as two, three, four, five, six,seven, eight, nine, ten, twenty, thirty, forty, fifty, or more portionswith different properties. For example, an appliance can include a firstappliance portion receiving a first subset of the patient's teeth and asecond appliance portion receiving a second subset of the patient'steeth, and the first and second portions can differ from each other withrespect to one or more of thickness, stiffness, or material composition.In some embodiments, the first and second portions can differ from eachother with respect to two or more of thickness, stiffness, or materialcomposition. In some embodiments, the first and second portions candiffer from each other with respect to thickness, stiffness, and/ormaterial composition, or any other appliance property described herein.

An appliance portion can include any part of an appliance, such as oneor more tooth-receiving cavities or portions thereof. The size andlocation of an appliance portion can be varied as desired. For example,an appliance portion can be arranged to receive and/or engage a subsetof the patient's teeth, such as a single tooth, a plurality of teeth, aportion of a tooth (e.g., a lingual, buccal, or occlusal surface), orcombinations thereof. In some embodiments, appliance portions thatreceive different subsets of teeth (e.g., anterior teeth, posteriorteeth, teeth to be repositioned, teeth to be retained in a currentposition) have different properties. Alternatively or in combination,appliance portions that engage different surfaces of the teeth (e.g.,buccal surfaces, lingual surfaces, occlusal surfaces) can have differentproperties. The use of orthodontic appliances with variable localizedproperties can allow for improved control over the forces and/or torquesto be applied to the patient's teeth, as described further herein.

In some embodiments, a property of an orthodontic appliance (e.g.,stiffness, thickness, material composition, etc.) varies along one ormore directions (e.g., mesial-distal direction, occlusal-gingivaldirection, buccal-lingual direction, anterior-posterior direction,interior-exterior direction), also referred to herein as a “functionallygraded property.” The property may vary gradually along the one or moredirections (e.g., vary according to a continuous function), or mayexhibit discrete changes (e.g., vary according to a non-continuousfunction such as a step function). The property may vary according to alinear or non-linear function, as desired.

Optionally, the directionality of a property of an orthodontic appliance(e.g., stiffness, thickness, material composition, etc.) may be varied.For example, mechanical properties of a material or structure of theappliance (e.g., stiffness, elongation, tensile strength, compressivestrength, bending properties, viscoelastic properties, etc.) may beanisotropic, such that the properties are different when measured alongx, y, and z directions. By changing the directionality of the structuresand/or materials of an appliance, varying properties can be developedalong different directions (e.g., mesial-distal direction,occlusal-gingival direction, buccal-lingual direction,anterior-posterior direction, interior-exterior direction). Suchvariations in directionality can be achieved using the directfabrication methods described herein, such as 3D printing.

In some embodiments, the orthodontic appliances with variable localizedproperties presented herein are produced by direct fabrication. Thedirect fabrication techniques presented herein may be particularlysuited for manufacturing of appliances with different localizedproperties that would otherwise be difficult to achieve with otherfabrication methods (e.g., indirect fabrication methods such asthermoforming a material sheet over a mold). For instance, in someembodiments, the direct fabrication techniques herein are used tofabricate orthodontic appliances exhibiting variable thicknesses,variable stiffnesses, and/or variable material compositions at differentportions of the appliance. Additional description of direct fabricationmethods suitable for producing the appliances of the present disclosureare provided further herein.

In some embodiments, direct fabrication is advantageous for producingappliances with variable thicknesses. In contrast to indirectfabrication methods such as thermoforming, in which the thickness of theresultant appliance is generally limited by the thickness of thethermoformed sheet, may vary based on the location of the appliance(e.g., gingival portions may experience more stretching duringthermoforming and thus may be thinner), and may be sensitive tovariations in process parameters (e.g., thermoforming temperature,vacuum pressure applied, material type, etc.), direct fabrication allowsfor control over the thickness of the fabricated appliance at anydesired location. For example, the thickness of an appliance may bevaried between one or more of the following locations: a buccal portion,a lingual portion, an occlusal portion, a gingival portion, an anteriorportion, a posterior portion, or combinations thereof. Optionally, anappliance can have a thickness varying from about 0.05 mm to about 8 mm,or from about 0.1 mm to about 2 mm. These values are provided asexamples only and not intended to be limiting. It shall be appreciatedthat the dimensions of the appliances herein can be varied as desired.In some embodiments, the minimum thickness of the appliance can be about10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the maximum thicknessof the appliance. The thickness of the appliance can be varied in orderto control the forces exerted by the appliance onto the patient's teeth.For example, relatively thick portions of the appliance can exert moreforce on the teeth (e.g., due to the increased stiffness of suchportions), while relatively thin portions of the appliance can exertless force on the teeth (e.g., due to the reduced stiffness of suchportions). Accordingly, the varying thicknesses of an appliance can beconfigured to apply a specified force system to a patient's teeth at anydesired location.

FIGS. 2A and 2B illustrate orthodontic appliances with varying occlusalthicknesses, in accordance with embodiments. Thicker occlusal portionscan be used to apply intrusion forces on selected teeth, while thinnerocclusal portions can be used where tooth intrusion is not desired. Insome embodiments, thinner occlusal portions can improve patient comfortby reducing the vertical spacing between the upper and lower arches, andcan help reduce open bite when wearing the appliance. Additionally,thinner occlusion portions may be beneficial for maintaining the naturalinterdigitation between upper and lower teeth during treatment. FIG. 2Aillustrates an appliance 200 including an upper shell 202 a and a lowershell 202 b. Each shell includes a thicker posterior occlusal portion204 a, 204 b, and a thinner anterior occlusal portion 206 a, 206 b. Theappliance 200 can be used to intrude the posterior teeth relative to theanterior teeth, e.g., to close an open bite. FIG. 2B illustrates anappliance 250 including an upper shell 252 a and a lower shell 252 b.Each shell includes a thinner posterior occlusal portion 254 a, 254 b,and a thicker anterior occlusal portion 256 a, 256 b. The thinnerposterior occlusal portion can be used to intrude the anterior teethrelative to the posterior teeth, e.g., to close a deep bite or overbite.In some embodiments, a thinner occlusal portion provides a better matchfor the natural articulation of the patient's jaws, e.g., to reducetemporomandibular joint issues.

In some embodiments, occlusal structures for controlling the relativepositioning (e.g., left-right, anterior-posterior, etc.) of the upperand lower jaws such as twin blocks, occlusal blocks, mandibularadvancement structures, and the like can be directly built into theappliance by varying the thickness of the occlusal surfaces. Theseocclusal structures can be used to correct various issues related to thepatient's bite, including but not limited to class II malocclusions,class III malocclusions, cross bite, open bite, and sleep apnea.Additional examples of integrally formed occlusal structures andfeatures suitable for use with the embodiments herein are discussedbelow.

FIGS. 3A and 3B illustrate orthodontic appliances with varyingthicknesses along a vertical direction, in accordance with embodiments.“Vertical” may be used herein to refer to the direction along the heightof a tooth crown, such that the thickness of one or more occlusalportions of the appliance differs from the thickness of one or moregingival portions of the appliance. FIG. 3A shows a cross-sectional viewof an appliance shell 300 having thicker gingival portions 302, 304 anda thinner occlusal surface 306. The shell 300 can be shaped to receive atooth crown 308, with the edges of the gingival portions 302, 304terminating above the gingiva. The thickened gingival portions 302, 304can be shaped to engage the undercuts of the tooth crown 308 in order tofacilitate extrusion of the tooth.

In some embodiments, an orthodontic appliance with varying thicknessesalong a vertical direction can be used to control movements of toothroots. FIG. 3B shows a cross-sectional view of an appliance shell 350having thicker gingival portions 352, 354 and a thinner occlusal surface356. The varying thickness of the shell 350 can result in larger forcesbeing delivered near the bottom of the tooth crown 358 closer to thecenter of resistance (e.g., arrow 360) and smaller forces beingdelivered near the top of the tooth crown away from the center ofresistance (e.g., arrow 362), thus resulting in a programmed motion ofthe tooth, e.g., along arrow 358. This approach can be advantageous forproducing tooth translation with reduced tipping, for example.

In some embodiments, force application structures such as protrusions,ridges, dimples, and the like can be integrally formed in the applianceby selectively increasing the thickness of the appliance shell at one ormore locations. A force application structure can extend inward from theinterior surface of the shell towards the received tooth in order todefine a contact point for application of force to the tooth. Anappliance can include one or more force application structures formed ona buccal surface, lingual surface, or occlusal surface of the shell, orcombinations thereof. With direct fabrication techniques, such forceapplication structures can be positioned and shaped with greateraccuracy, thus providing precise control over the magnitude anddirection of the resultant forces exerted on the teeth. Additionally,direct fabrication also permits more precise control over surroundingtooth contact points compared to other fabrication methods (e.g.,thermoforming).

FIG. 4A shows a cross-sectional view of an exemplary force applicationstructure 400, in accordance with embodiments. The structure 400 isformed as a thickened protrusion 402 within an appliance wall 404. Insome embodiments, the thickness of the portions of the wall 404 near theprotrusion 402 can be varied (e.g., increased or decreased) in order tocontrol the stiffness of the appliance near the protrusion 402. Forexample, the wall 404 can include a thinner portion 406 adjacent theprotrusion 402 to decrease the local stiffness in order to extend theworking range of the protrusion 402.

FIG. 4B shows a cross-sectional view of another exemplary forceapplication structure 410, in accordance with embodiments. The structure410 is formed as a corrugated portion 412 within an appliance wall 414.Similar to the structure 400, the portions of the wall 414 near thecorrugated portion 412 can be varied (e.g., increased or decreased) inorder to control the stiffness of the appliance near the corrugatedportion 412. For example, the wall 424 can include a thinner portion 416adjacent the corrugated portion 412 to decrease the local stiffness inorder to extend the working range of the corrugated portion 412.

FIG. 4C shows a cross-sectional view of an appliance shell 420 withforce application structures for controlling tooth tipping and/ortorque, in accordance with embodiments. The shell 420 includes a buccalforce application structure 422 and a lingual force applicationstructure 424. Although the force application structures 422, 424 aredepicted in FIG. 4C as protrusions or ridges, other types of structurescan be used in alternative embodiments. The buccal and lingualstructures 422, 424 can engage and apply forces to a received tooth 426.In some embodiments, the buccal structure 422 is positioned near thebottom of the tooth crown while the lingual structure 424 is positionednear the top of the tooth crown in order to control tipping of the tooth426. It shall be appreciated that alternative configurations of thebuccal and lingual structures 422, 424 can also be used to controltipping, e.g., a configuration with the buccal structure 422 locatednear the top of the crown and the lingual structure 424 located near thebottom of the crown.

FIG. 4D shows a cross-sectional view of an appliance shell 430 withforce application structures for controlling tooth root movements, inaccordance with embodiments. The shell 430 includes a mesial forceapplication structure 432 and a distal force application structure 434,depicted herein as protrusions. The mesial structure 432 is positionednear the top of the tooth crown 436 and the distal structure 434 ispositioned near the bottom of the tooth crown 436 in order to controlmovements of the tooth root. It shall be appreciated that theconfiguration can be reversed, e.g., with the mesial structure 432 nearthe bottom and the distal structure 434 near the top. In someembodiments, this configuration permits bodily translation of the entiretooth along the mesial-distal direction with reduced tipping.

FIG. 4E shows a cross-sectional occlusal view of an appliance shell 440with force application structures for controlling tooth rotation, inaccordance with embodiments. The shell 440 includes a pair of forceapplication structures 442, 444 positioned to engage opposing sides ofthe tooth 446 (e.g., buccal and lingual sides) in order to create aforce couple that produces rotation of the tooth 446 (e.g., along arrow448).

Variations in the thickness of an appliance shell can also be used toform other types of functional structures in the appliances herein, andsuch structures may be configured to perform functions in addition to orother than application of forces to the teeth, such as improving ease ofuse and patient comfort. The direct fabrication methods presented hereinprovide improved flexibility and control over the geometry andpositioning of such structure on an orthodontic appliance.

FIG. 5A illustrates an appliance 500 with built-in handle structures502, 504 in the appliance shell 506, in accordance with embodiments. Thehandle structures 502, 504 can be used to facilitate removal of theappliance 500 from the patient's teeth. The number and positioning ofthe handle structures can be varied as desired. In the depictedembodiment, the handle structures 502, 504 are respectively positionedon the right and left buccal surfaces of the shell 506 near the distalportions.

FIGS. 5B through 5D illustrate exemplary geometries for handlestructures, in accordance with embodiments. FIG. 5B illustrates a shell510 in which a gingival edge 512 is flared outwards away from thereceived tooth 514 in order to form a handle structure. FIG. 5Cillustrates a shell 520 having a handle structure 522 positioned flushwith the gingival edge of the shell 520. FIG. 5D illustrates a shell 530having a handle structure 522 that is offset from the gingival edge ofthe shell 530.

FIG. 6 illustrates a cross-sectional view of an appliance shell 600 withgingival edges 602, 604 shaped to improve patient comfort, in accordancewith embodiments. The edges 602, 604 can be formed into a smooth shape,such as a beveled or rounded shape, in order to reduce irritation ofgingival tissues when the appliance is worn.

In some embodiments, the appliances discussed herein have variablelocalized stiffnesses. As discussed above and herein, variations instiffness can influence the forces that are applied to the teeth, withstiffer portions applying more force and elastic portions applying lessforce. The stiffness of an appliance can be within a range from about0.1 N/mm to about 1000 N/mm. The stiffness of an appliance can berelated to its elastic modulus, and the elastic modulus of an appliancecan be within a range from about 10,000 psi to about 700,000 psi. Thesevalues are provided as examples only and not intended to be limiting. Itshall be appreciated that the elastic modulus, stiffness, and otherproperties of the appliances herein can be varied as desired. In someembodiments, the minimum stiffness of the appliance can be about 0.001%,0.01%, 0.1%, 1%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of themaximum stiffness of the appliance.

The stiffness of an appliance portion can depend on both the geometry ofthe portion and the elastic modulus of the material used to form thatportion. For example, the thickness of an appliance can influence thestiffness of the appliance, with thicker portions being more stiff andthinner portions being more compliant. Accordingly, in some embodiments,appliance thickness is locally varied in order to selectively modulatethe stiffness of the appliance. This approach allows for variations instiffness to be achieved based only on the appliance geometry, withoutusing multiple material types or different curing parameters. However,it shall be appreciated that although certain embodiments hereindescribe control of appliance stiffness using variable thicknesses,other approaches disclosed herein such as variable photopolymerizationand/or variable material compositions can also be used to achievesimilar results, and that such approaches can be combined with orsubstituted for any of the thickness-based approaches described herein.For example, variations in stiffness can also be achieved by usingmaterials with different elastic moduli.

FIG. 7 illustrates an appliance 700 with one or more thickened ribs 702for increased stiffness, in accordance with embodiments. The ribs 702can be built integrally into the appliance shell 704 using the directfabrication methods described herein. The number, geometry, andconfiguration of the ribs 702 can be configured to increase thestiffness of the appliance at certain locations. For example, in thedepicted embodiment, the ribs 702 are positioned on the buccal surfaceof the shell 704 near the canines and extend longitudinally along themesial-distal axis. This can be beneficial for reducing flexing of theshell 704 near the canines when modifying the width of the arch, e.g.,by moving the molars and/or biscuspids buccally or lingually (see, e.g.,arrows 706). It shall be appreciated that in alternative embodiments,the ribs 702 can be positioned at other locations on the shell 704,e.g., on a lingual surface, occlusal surface, near the anterior teeth,near the posterior teeth, etc., in order to increase the stiffness ofthe appliance at those locations.

FIG. 8 illustrates an appliance 800 with a plurality of thinner regions802 for reduced stiffness, in accordance with embodiments. The thinnerregions 802 can be formed integrally in the shell 804 using the directfabrication methods described herein. In some embodiments, the thinnerregions 802 are formed in the buccal surface of the shell 804 asrecesses that extend only partially through the thickness of the shell804. In alternative embodiments, the regions 802 form openings in theshell 804 that extend through the entire thickness of the shell 804. Thenumber, geometry, and configuration of the regions 802 can be configuredto selectively reduce the stiffness of the appliance at certainlocations. For instance, one or more thinner regions 802 can be formedon a buccal surface, on a lingual surface, occlusal surface, near theanterior teeth, near the posterior teeth, or combinations thereof.

In some embodiments, variations in stiffness and/or other materialproperties of the appliance can be achieved independently from theappliance geometry. For example, it may be desirable in some instancesto produce a variable stiffness appliance while maintaining asubstantially uniform appliance thickness. In such embodiments, this canbe achieved by varying the degree of photopolymerization of differentportions of the appliance during the direct fabrication process. Asdiscussed further herein, some embodiments of the direct fabricationmethods herein involve curing a photopolymer by irradiation with lightin order to selectively polymerize the photopolymer and thereby build upthe appliance geometry. The extent to which each appliance portion ispolymerized can be controlled by modifying the curing parameters, whichinclude but are not limited to curing time, power, spacing, and/ordepth. In some embodiments, portions of the appliance exhibiting agreater degree of photopolymerization have increased stiffness andmodulus compared to portions exhibiting a lesser degree ofphotopolymerization. Control of photopolymerization allows for theproduction of variable stiffness appliances without varying theappliance geometry (e.g., thickness) or material composition. However,it shall be appreciated that although certain embodiments hereindescribe control of appliance stiffness using variablephotopolymerization, other approaches disclosed herein such as variablethicknesses and/or variable material compositions can also be used toachieve similar results, and that such approaches can be combined withor substituted for any of the photopolymerization-based approachesdescribed herein.

FIG. 9 shows a cross-sectional view of an appliance shell 900 withvarying degrees of photopolymerization, in accordance with embodiments.The shell 900 includes a stiff portion 902 having a relatively highstiffness, an intermediate portion 904 having an intermediate stiffness,and an elastic portion 906 having a relative low stiffness. In someembodiments, the differing stiffnesses of the portions 902, 904, and 906is achieved by varying the degree of photopolymerization in each of theportions. The portions 902, 904, and 906 can be arranged such that theshell 900 is stiffer towards the gingival portion and softer towards theocclusal surface. For example, in the depicted embodiment, the stiffportion 902 is located near the gingival portion of the shell 900, theelastic portion 906 is located near the occlusal portion of the shell900, and the intermediate portion 904 is positioned between the stiffportion 902 and the elastic portion 906. The configuration of the shell900 can result in a variable force profile 908 applied to the receivedtooth 910 in which the magnitude of the force vectors decreases movingfrom the gingival portion of the tooth 910 to the occlusal portion ofthe tooth 910. The force profile 908 can be advantageous for elicitingroot translation of the tooth 910 without using attachments.

FIG. 10 shows a cross-sectional view of an appliance shell 1000configured for tooth rotation, in accordance with embodiments. The shell1000 can include a stiff band 1002 positioned between an occlusalelastic section 1004 and a gingival elastic section 1006 and extendingalong the buccal and/or lingual surfaces of a received tooth. In someembodiments, the stiff band 1002 is configured with a programmedrotation when the shell 1000 is worn on a tooth, while the surroundingelastic sections 1004, 1006 have a lower stiffness and are notconfigured with programmed rotation. Accordingly, during use,displacement occurs primarily at the elastic sections 1004, 1006 ratherthan at the stiff band 1002. The combination of such features within asingle shell 1000 can be used to apply moment or torque onto the toothin order to produce a rotation of the tooth, e.g., about the axis 1008,with a greater working range than if the shell 1000 were made of asingle material with homogeneous properties.

FIG. 11A illustrates an appliance 1100 with a plurality of forceisolated segments 1102, in accordance with embodiments. The segments1102 are joined to each other by an elastic portion 1104. In someembodiments, the segments 1102 are stiffer than the elastic portion1104, and the varying stiffnesses can be produced by direct fabricationphotopolymerization control, variations in thickness, and/or variationsin material composition, as discussed herein. By separating the segments1102 with the elastic portion 1104, the forces exerted by the respectivesegments can be isolated from each other, thus permitting independentforce application on different groups of teeth. Although the depictedembodiment shows two segments 1102 joined by a single elastic portion1104, it shall be appreciated that the number of segments and elasticportions can be varied as desired. Furthermore, although the depictedembodiment shows segments that are separated horizontally along ananterior-posterior direction, it shall be appreciated that theapproaches herein are equally applicable to segments separated alongother directions, such as segments separated vertically along anocclusal-gingival direction.

FIG. 11B illustrates an appliance 1110 configured for force transferbetween a plurality of force isolated segments 1112, in accordance withembodiments. Similar to the appliance 1100, the segments 1112 are joinedto each other by a relatively elastic portion 1114, and thisconfiguration isolates the forces generated by the respective segments.In some embodiments, it may be desirable to provide some amount of forcetransfer between the segments 1112. This can be achieved by coupling thesegments 1112 to each other by a connector 1116, depicted herein as abar or band. The connector 1116 can have a stiffness greater than thatof the elastic portion 1114. The stiffness of the connector 1116 can begreater than or less than the stiffness of the segments 1112, asdesired. The connector 1116 can be used to isolate forces from the teethreceived in the elastic portion 1114 while permitting the transfer ofselected forces between the teeth received by segments 1112.

FIG. 11C illustrates an exemplary force transfer configuration, inaccordance with embodiments. Similar to the other embodiments herein,the configuration includes a first segment 1120 and second segment 1122separated by an elastic portion 1124. A connector 1126 is used to couplethe first and second segments 1120, 1122 to each other. The connector1126 can also be coupled along its length to the elastic portion 1124 inorder to permit some transfer of force to the elastic portion 1124.

FIG. 11D illustrates another exemplary force transfer configuration, inaccordance with embodiments. Similar to the other embodiments herein,the configuration includes a first segment 1130 and second segment 1132separated by an elastic portion 1134. A connector 1136 is used to couplethe first and second segments 1130, 1132 to each other. The connector1136 can be separated from the elastic portion 1134 so as to isolate theelastic portion 1134 from the forces produced by the first and secondsegments 1130, 1132.

FIG. 11E illustrates an appliance 1140 with a plurality of segments1142, 1143 used in combination with an elastic 1144, in accordance withembodiments. Similar to the other embodiments discussed herein, thesegments 1142, 1143 can be joined to each other by an elastic portion1146 in order to isolate groups of teeth from each other. The elastic1144 is respectively coupled to a first segment 1142 at a first couplingpoint 1148 and to a second segment 1143 at a second coupling point 1150,such that the length of the elastic 1144 spans the elastic portion 1146and is aligned with the anterior-posterior axis of the appliance 1140.The elastic 1144 can be permanently or removably coupled to the segments1142, 1143 in a variety of ways, e.g., using fasteners, hooks,adhesives, and the like. In alternative embodiments, the appliance 1140can be formed with a built-in elastic 1144 such that no separatecoupling step is needed, as discussed further herein.

In some embodiments, the appliance 1140 is configured such that theelastic 1144 is placed in tension when it is coupled to the segments1142, 1143 via the coupling points 1148, 1150. Accordingly, the elastic1144 exerts tensile forces on the segments 1142, 1143 that pull themtowards each other. These forces can be transmitted to the teethreceived by the segments 1142, 1143 in order to move them towards eachother, e.g., to close a space between the teeth, retract a group ofteeth, and so on. The use of an elastic portion 1146 to isolate groupsof teeth to be moved can provide an increased working range for theelastic 1144.

FIG. 11F illustrates an appliance 1160 with a plurality of segments1162, 1163 used in combination with an elastic 1164, in accordance withembodiments. Similar to the other embodiments herein, the segments 1162,1163 are joined to each other by an elastic portion 1166. The elastic1164 is coupled to one of the segments 1162 at a first coupling point1168 and to a location on the patient's opposing jaw at a secondcoupling point 1170. For example, the second coupling point 1170 of theelastic 1164 can be attached to another appliance worn on the opposingjaw, a tooth-mounted attachment on a tooth on the opposing jaw, ananchoring device positioned in bone of the opposing jaw, or combinationsthereof. The elastic 1164 may be placed in tension when coupled to thesegment 1162 and the opposing jaw, and the tensile forces can be appliedonto the teeth received by the segment 1162 in order to elicit movementsof the teeth (e.g., retraction). The elastic portion 1166 can isolatethe forces applied onto the teeth received by the segment 1163 from theforces applied to the teeth received by the segment 1162, such that thetensile forces exerted by the elastic 1164 act primarily on the teethreceived by the segment 1162 and have little or no effect on the teethreceived by the segment 1163. This approach can be used, for example, toisolate one or more anterior teeth from one or more posterior teeth, orvice-versa.

In some embodiments, appliances with heterogeneous properties asdiscussed herein can be produced by forming the appliance from aplurality of different materials. In some embodiments, different typesof material are used to form different portions of the appliance, andthe different properties of the different material types can eachcontribute to the properties of the resultant appliance. The materialsused to fabricate an appliance can vary from each other with respect toone or more of color, translucency, elastic modulus, surface strength,biocompatibility, and/or curing properties, to name a few. For instance,a relatively stiff or rigid material can be deposited at locations whereincreased stiffness is desired, and a relatively elastic material can bedeposited at locations where increased elasticity is desired.Alternatively, rather than forming each appliance portion from a singlematerial type, multiple materials can be combined and used to form anappliance portion. The amounts and/or types of materials used candetermine the properties of the corresponding appliance portion. In someembodiments, multiple materials can be mixed or otherwise combined witheach other in order to form a composite that exhibits superiorproperties compared to the individual materials. The amounts and/ortypes of materials used in the composite can control the resultantproperties (e.g., stiffness) of the composite. Accordingly, applianceswith heterogeneous properties as discussed herein can be produced byusing different composites to form different portions of the appliance.

The arrangement (or topology) of multiple materials in an appliance canbe varied as desired. For example, multiple materials can be formed onan appliance in discrete sections, compartments, or layers.Alternatively, the multiple materials can be formed as a continuousmixture such that individual material types are not compartmentalized.The locations where different material types are formed can be varied asdesired. For instance, portions of the appliance adjacent the gingivamay be formed from a softer or more elastic material than portionsadjacent the teeth, or vice-versa. As another example, portions of theappliance adjacent the interproximal regions of the teeth may be formedfrom a softer or more elastic material than portions away from theinterproximal regions, or vice-versa. In another example, interiorportions of the appliance near the teeth may be formed from a softer ormore elastic material than exterior portions away from the teeth, orvice-versa. In yet another example, portions of the appliance used toengage and apply forces to teeth (e.g., directly or indirectly via anattachment) may be formed from a softer or more elastic material thanportions that do not engage the teeth, or vice-versa. In yet anotherexample, portions of the appliance used to engage other appliances ordevices (e.g., elastics, springs, wires, etc.) may be formed from asofter or more elastic material than portions that do not engage otherappliances or devices, or vice-versa.

The multi-material approaches described herein permit the fabrication ofheterogeneous appliances without varying the geometry (e.g., thickness)and/or photopolymerization parameters of the appliance. However, itshall be appreciated that although certain embodiments herein describecontrol of appliance stiffness using variable material compositions,other approaches disclosed herein such as variable photopolymerizationand/or variable thicknesses can also be used to achieve similar results,and that such approaches can be combined with or substituted for any ofthe multi-material approaches described herein.

FIG. 12A illustrates an appliance 1200 with different materials used forthe occlusal portion 1202 and gingival portion 1204, in accordance withembodiments. Based on the properties of the respective materials used,the occlusal portion 1202 can have a greater stiffness than the gingivalportion 1204, or vice-versa. The material properties for each of theportions can be determined based on the desired functionalities for theocclusal and gingival portions. For example, in some embodiments, theocclusal portion 1202 can be formed from a relatively soft or elasticmaterial, while the gingival portion 1204 can be formed from arelatively hard or stiff material. In such embodiments, the relativelyelastic occlusal portion 1202 can act as a “chewy” that the patient canbite down on in order to facilitate proper seating of the appliance 1200on the patient's teeth. Moreover, the use of a relatively elasticocclusal portion 1202 can potentially reduce the extent of posterioropen bite caused by wearing the appliance 1200, as well as provideimproved engagement of the appliance 1200 with the patient's teeth withless interference from the occlusal surfaces. Alternatively, theocclusal portion 1202 can be formed from a relatively hard or stiffmaterial and the gingival portion 1204 can be formed from a relativelysoft or elastic material. This configuration can be advantageous forimproving durability of the occlusal surfaces, e.g., in order to resistwear due to bruxism, allow the patient to consume certain foods whilewearing the appliance 1200, etc.

FIG. 12B illustrates an appliance 1250 with different materials used forthe buccal portion 1252 and lingual portion 1254, in accordance withembodiments. Based on the properties of the respective materials used,the buccal portion 1252 can have a greater stiffness than the lingualportion 1254, or vice-versa. The material properties for each of theportions can be determined based on the desired functionalities for thebuccal and lingual portions. For example, in some embodiments, thebuccal portion 1252 can be formed from a relatively soft or elasticmaterial, while the lingual portion 1254 can be formed from a relativelyhard or stiff material. Optionally, the buccal portion 1252 can beformed from a clear material for improved aesthetics, while the lingualportion 1254 is not readily visible and therefore does not need to beformed from a clear material. In some embodiments, the relativestiffness of the buccal portion 1252 is advantageous for improvingengagement of the appliance 1250 with tooth-mounted attachments, as suchattachments are frequently positioned on the buccal surfaces of teeth.The relative stiffness of the lingual surface can exert forces forproducing tooth movements in a buccal direction, e.g., for archexpansion.

In some embodiments, it can be advantageous to design an applianceexhibiting variable stiffness along different directions. The stiffnessof an appliance portion along a vertical direction, horizontaldirection, lateral direction, mesial-distal direction,anterior-posterior direction, occlusal-gingival direction, and/orbuccal-lingual direction may differ from the stiffness of the applianceportion along a vertical direction, horizontal direction, lateraldirection, mesial-distal direction, anterior-posterior direction,occlusal-gingival direction, and/or buccal-lingual direction. Thevariable directional stiffness can allow for different forces to bepreferentially applied along certain directions. For instance, it may bedesirable to apply more force along an anterior-posterior direction andless force along an intrusion or extrusion direction, or vice-versa. Asanother example, it may be desirable to apply one force on the left sideof an appliance and a different force on the right side of theappliance. In another example, it may be desirable to apply a largerrotation force on one tooth (e.g., a molar) and a smaller rotation forceon an adjacent tooth (e.g., a bicuspid). Variable force applicationalong different directions can be achieved using any of the methodspresented herein, including varying the thickness, degree ofphotopolymerization, and/or material composition.

FIG. 13 illustrates an appliance 1300 with variable stiffness alongdifferent directions for uprighting a tooth 1302, in accordance withembodiments. The appliance 1300 can be configured to create a “rootfirst tipping chain” in which adjacent teeth 1304, 1306 flanking thetooth 1302 provide anchorage for exerting tipping forces onto the tooth1302 in order to move the tooth 1302 into a more upright position, e.g.,along the movement path indicated by arrow 1308. In some embodiments,the appliance 1300 includes an appliance shell (not shown) with cavitiesto receive the tooth 1302 and the adjacent anchor teeth 1304, 1306. Theshell can be formed with clearance space around the target tooth 1302 inorder to accommodate the uprighting movement of the tooth 1302. Theshell can be shaped to engage the tooth 1302 in order to exerttransverse forces 1310 to upright the tooth 1302. Additionally, theappliance 1300 can include a stiff band of material 1312 that spans thetooth 1302 and the adjacent anchor teeth 1304, 1306. The geometry andlocation of the stiff band 1312 can be configured to alter the center ofrotation 1314 of the tooth 1302 in order to produce the uprightingmovement. For example, the stiff band 1312 can be shaped according tothe geometry of the tooth 1302 in order to move the center of rotation1314 for a given translational movement towards the occlusal surface ofthe tooth. This approach can fix the occlusal surface of the tooth crownat a specified location, and the translational force applied to thetooth 1302 thus rotates the entire tooth 1302 about the specifiedlocation. In some embodiments, by changing the center of rotation 1314,the tooth 1302 can be moved in a “root first” fashion in whichrepositioning of the tooth root precedes repositioning of the toothcrown. In some embodiments, a root first movement involves atranslational movement of the tooth root greater than translationalmovement of the tooth crown.

In some embodiments, the use of variable stiffness appliances asdescribed herein can be used to reduce or eliminate unwanted pairings ofmovements and/or forces that may occur. For example, tooth movementssuch as root control movements, tipping, and the like may cause unwantedintrusion or extrusion of the target tooth and/or surrounding teeth. Insome embodiments, unwanted movements and/or forces can be reduced oreliminated by varying the directional stiffness of the appliance usingthe methods provided herein (e.g., variable stiffness, variable materialproperties, variable material compositions, etc.). An appliance withvarying directional stiffnesses may exhibit anisotropic properties, suchthat the stiffness along one direction may differ from the stiffnessalong at least one other direction, for example. In some embodiments,the appliance is configured with an increased stiffness in one or moredirections along a desired tooth movement and a reduced stiffness in oneor more directions along an undesired tooth movement (e.g., away fromthe desired tooth movement) in order to preferentially elicit thedesired movement while reducing or eliminating the undesired movement.

FIGS. 14A through 14C schematically illustrate reductions in unwantedpairing of movements using varying directional stiffnesses, inaccordance with embodiments. FIG. 14A illustrates an appliance portion1400 that is relatively stiff along a transverse direction 1402 andrelatively elastic along a vertical direction 1404 in order to elicittransverse tooth movements (e.g., translation) while reducing oreliminating unwanted vertical movements (e.g., extrusion or intrusion).Alternatively, if vertical movements are desired while transversemovements are unwanted, the relative stiffnesses can be reversed so thatthe portion 1400 exhibits increased stiffness along the verticaldirection 1404 and reduced stiffness along the transverse direction1402. FIGS. 14B and 14C illustrate top and side views, respectively, ofan appliance portion 1410 that is relatively stiff in a rotationaldirection 1412 and relatively elastic along a vertical direction 1414 inorder to produce tooth rotation or torsion while reducing or eliminatingunwanted vertical movements (e.g., extrusion or intrusion). Theconfiguration can be reversed if vertical movements are desired whilerotational movements are undesired, such that the portion 1410 isrelatively elastic along the rotational direction 1412 and relativelystiff along the vertical direction 1414.

Although the orthodontic appliances with variable properties herein havebeen described primarily in the context of variable stiffness,thickness, and/or material composition, it shall be appreciated that anorthodontic appliance may exhibit variations in other properties aswell, such as one or more of hardness, strength, compressibility, stressrelaxation, hydrophobicity/hydrophilicity, Poisson ratio, strain rate,viscoelasticity, or polarity, to name a few. For example, an appliancecan be fabricated with heterogeneous hydrophobicity/hydrophilicity,e.g., with hydrophilic inner surfaces (e.g., surfaces near the receivedteeth) in order to improve appliance wetting and grip on the teeth, andwith hydrophobic outer surfaces (e.g., away from the received teeth) inorder to reduce saliva diffusion and stress relaxation. The directfabrication methods herein can be used to produce appliances exhibitingcomplex and heterogeneous combinations of many different materialproperties.

Orthodontic Appliances with Integrally Formed Components

Orthodontic treatment with fixed repositioning devices, such as braces,may be used in conjunction with auxiliary components, devices, oraccessories to achieve desired end results. Such auxiliary componentsmay take a variety of forms ranging from readily available traditionalaccessories to specially created devices. Auxiliary components may bemounted on fixed, non-removable devices or they may be part of aremovable appliance typically worn prior to the application of the fixeddevices Similarly, it may be desired to utilize auxiliary componentswhen repositioning teeth with removable tooth repositioning appliances,such as the shell appliances described herein. In some embodiments, suchauxiliary components are affixed to a shell appliance after the shellappliance has been initially fabricated (e.g., by thermoforming).

The direct fabrication approaches presented herein can be used toproduce orthodontic appliances with various types of built-incomponents, also referred to herein as an “integrally formed component”or an “integrally formed feature.” Examples of integrally formedcomponents include, but are not limited to: a hook, button, groove,slit, slide block, slide column, slide cylinder, corrugation, undercut,internal structure, hole, connection, snap, bevel, mating, guide,channel, block, recess, cavity, chamber, scaffold, layer, a coating, orany other structure or feature as described in U.S. Patent PublicationNo. 2007/0231765, U.S. Pat. No. 8,641,414, and U.S. Patent PublicationNo. 2011/0269092, the disclosures of which are incorporated herein byreference in their entirety. An integrally formed component can includeor be designed to substitute for one or more of the following auxiliarycomponents: elastics, wires, springs, bars, arch expanders, palatalexpanders, twin blocks, occlusal blocks, bite ramps, mandibularadvancement splints, bite plates, pontics, hooks, brackets, headgeartubes, bumper tubes, palatal bars, frameworks, pin-and-tube apparatuses,buccal shields, buccinator bows, wire shields, lingual flanges and pads,lip pads or bumpers, protrusions, divots, or any other structure orfeature suitable for use in conjunction with the appliances herein totreat a patient. The direct fabrication methods provided herein allowsuch auxiliary components to be integrally formed with an applianceshell, as discussed further below.

As used herein, an “integrally formed component” or “integrally formedfeature” may refer to a component formed as a single unitary ormonolithic piece with the appliance shell, such that the componentcannot be separated from the appliance without damaging or destroyingthe appliance. An integrally formed component may be differentiated froma component that is formed and/or provided separately from the shell andis subsequently coupled to the shell (e.g., by adhesives, fasteners,etc.). In some embodiments, an integrally formed component isconcurrently formed with the shell in a single manufacturing orfabrication step, such that the same fabrication machine and/orfabrication process is used to produce both the component and the shell.Accordingly, an integrally formed component may be differentiated from acomponent that is formed prior to or after the shell is formed, and maybe differentiated from a component that is formed using a differentfabrication process than the process used to form the shell. Forexample, the various direct fabrication methods discussed herein can beused to produce both the appliance shell and the integrally formedcomponent concurrently in a single fabrication step.

In some embodiments, an integrally formed component of an orthodonticappliance may be an orthodontic component or accessory. Orthodonticcomponents or accessories can include but are not limited to accessoriestypically used with fixed, non-removable orthodontic devices. Forexample, headgear tubes are accessories typically mounted on traditionalbraces for inserting a headgear device and applying extraoral force tothe teeth and jaws. Tubes for receiving headgear may be integrallyformed in the shell of an appliance for a similar effect. Similarly,orthodontic hooks may be mounted on traditional braces to supportelastic bands which may also apply distinct forces to the teeth andjaws. As with headgear tubes, such hooks may also be integrally formedin the shell of a shell appliance for a similar effect. Likewise, anumber of other accessories, such as brackets, springs, bumper tubes,palatal bars, frameworks, pin-and-tube apparatuses and the like, may beintegrally formed into shell appliances. In some embodiments, such aswith brackets, the accessory may be used to join a removable shellappliance with a portion of teeth supporting fixed conventional devices,such as braces. An orthodontic component or accessory coupled to anappliance via integrally formed mounting features can be configured tointeract with any other orthodontic appliances present in the patient'smouth.

In some embodiments, an integrally formed component may be anorthodontic component or accessory that is primarily exclusive toremovable appliances. These components may not be suited for use withfixed appliances and devices, e.g., due to their bulk and size. In someembodiments, such components are used prior to the use of fixed devicesto create a favorable environment for later tooth repositioning. Forexample, when a patient's teeth are still erupting, a number of featuresmay be used to foster improved eruption and development of the tootharrangement and bite configuration. These may include buccal shields,buccinator bows or wire shields, bite plates, palatal expanders andbars, lingual flanges and pads, lip pads or bumpers, and the like. Sincethese components are currently used with removable appliances, they areideally suited for use with the appliances described herein.Accordingly, the features may be integrally formed in the polymericshell of an appliance. Similarly, supporting structures for suchcomponents may also be integrally formed in the shell for the removableapplication of a component. For example, a bumper tube may be embeddedin the polymeric shell for later insertion and removal of a bumper.

In some embodiments, an appliance may be directly fabricated with anintegrally formed component such that use of the appliance comprisingthe integral component provides orthodontic therapy in conjunction withother types of dental and periodontal therapies (e.g., to improve oralhealth, for cosmetic purposes, etc.) which may be desired or required bythe patient. In addition, producing the orthodontic appliance comprisingthe integrally formed component in a single fabrication step caneliminate additional steps that were previously required in order toattach an auxiliary component to an appliance, and can thereforestreamline manufacturing. Benefits of streamlined manufacturing includereduced cost, reduced number of steps, fewer materials, fasterproduction, and reduced rates of error, among others. Additionally,available geometries, types of materials that could be used, types ofcomponents that could be formed, location of the components within theappliance, and the like are broader with an integrally formed componentcompared to those previously considered for an externally attachedcomponent. Often, the resolution by which an integrally formed componentcan be designed and fabricated is more precise compared to externallyattached components.

An added advantage of the use of appliances comprising integrally formedcomponents is the ability to provide the conventional benefit of theauxiliary component while simultaneously repositioning the teeth. Infixed appliance treatment, for example, the fixed appliance may precludethe ability to simultaneously use auxiliary components provided asremovable appliances since removable appliances may not be readilyapplied with fixed appliances in place. For example, situations in whichit is desired to control eruption of specific teeth concomitant withrepositioning of the same or other teeth may be difficult to achievewith fixed appliances.

Accordingly, systems, methods, and devices for orthodontic applianceswith an integrally formed component are provided herein. The componentcan be any structure or feature formed into an appliance shell of theapparatus for facilitating attachment of the appliance shell to anadditional device. Often the integrally formed component is shaped toengage with, receive, couple to, connect with, and/or mate with acomplementary shape of a patient's tooth or an additional appliance or aportion thereof. As described further herein, such components caninclude, but are not limited to a hook, button, groove, slit, slideblock, slide column, slide cylinder corrugation, undercut, internalstructure, hole, connection, snap, bevel, mating, guide, channel, block,recess, cavity, chamber, scaffold, layer, coating, and the like. As usedherein, “integrally formed feature” may refer to a feature formed as asingle unitary or monolithic piece with another appliance component(e.g., an appliance shell with teeth receiving cavities), such that thefeature cannot be separated from the appliance without damaging ordestroying the appliance component.

During a course of orthodontic treatment, it may be desired or necessaryto apply a force to a patient's teeth to generate movement of one ormore teeth to bring the patient's teeth into a better occlusion. Toothmovements that may be generated by the appliances herein include but arenot limited to tipping, torqueing, rotating, translating, extruding, orintruding. In many instances, it may not be possible to generate desiredlevels of such a force solely through the use of a shell appliancewithout any additional auxiliary component, feature, component,characteristic or the like. Thus, in some embodiments, the forcesgenerated by such a shell are supplemented by the forces produced by anintegrally formed component. In some embodiments, integrally formedcomponents are used to increase an amount of force applied to the teeth,decrease an amount of force applied to the teeth, and/or change thedistribution of force applied to the teeth, relative to the force(s)exerted by the appliance in the absence of such components.

In one aspect, a method for fabricating an orthodontic appliancecomprising an integrally formed component is provided. The method cancomprise: determining a movement path to move one or more teeth from aninitial arrangement to a target arrangement; determining an appliancegeometry for an orthodontic appliance comprising a shell and one or moreintegrally formed components, wherein the shell comprises a plurality ofteeth receiving cavities shaped to move the one or more teeth from theinitial arrangement to the target arrangement; and generatinginstructions for direct fabrication of the orthodontic appliance,wherein the instructions are configured to cause direct fabrication ofthe shell using a first material and direct fabrication of the one ormore integrally formed components using a second, different material.

In some embodiments, the first material differs from the second materialwith respect to one or more of the following: stiffness, elasticmodulus, hardness, thickness, strength, compressibility, stressrelaxation, hydrophobicity, hydrophilicity, Poisson ratio, strain rate,viscoelasticity, or polarity.

In some embodiments, the method further comprises: determining a firstmaterial composition for the shell, the first material compositioncomprising the first material; and determining a second materialcomposition for the integrally formed component, the second materialcomposition comprising the second material.

In some embodiments, the direct fabrication technique is an additivemanufacturing technique or a subtractive manufacturing technique. Theadditive manufacturing technique can comprise one or more of: vatphotopolymerization, material jetting, binder jetting, materialextrusion, powder bed fusion, sheet lamination, or directed energydeposition.

In some embodiments, the one or more integrally formed componentscomprise or are designed to substitute for an elastic, a wire, or aspring.

In some embodiments, the one or more integrally formed componentscomprise or are designed to substitute for an arch expander, a palatalexpander, or a palatal bar.

In some embodiments, the one or more integrally formed componentscomprise or are designed to substitute for a twin block, an occlusalblock, a bite ramp, an advancement structure, or a bite plate.

In some embodiments, the one or more integrally formed components areshaped to couple between a first portion and a second portion of theshell.

In some embodiments, the shell is shaped to be worn on a jaw of thepatient and the one or more integrally formed components are shaped tocouple to an appliance worn on an opposing jaw of the patient.

In some embodiments, the one or more integrally formed componentscomprise one or more mounting features shaped to couple to an auxiliarycomponent.

In another aspect, a system for fabricating an orthodontic appliancecomprising an integrally formed component is provided. The system cancomprise one or more processors configured with instructions to:determine a movement path to move one or more teeth from an initialarrangement to a target arrangement; determine an appliance geometry foran orthodontic appliance comprising a shell and one or more integrallyformed components, wherein the shell comprises a plurality of teethreceiving cavities shaped to move the one or more teeth from the initialarrangement to the target arrangement; and generate instructions fordirect fabrication of the orthodontic appliance, wherein theinstructions are configured to cause direct fabrication of the shellusing a first material and direct fabrication of the one or moreintegrally formed components using a second, different material.

In some embodiments, the first material differs from the second materialwith respect to one or more of the following: stiffness, elasticmodulus, hardness, thickness, strength, compressibility, stressrelaxation, hydrophobicity, hydrophilicity, Poisson ratio, strain rate,viscoelasticity, or polarity.

In some embodiments, the one or more processors are further configuredwith instructions to: determine a first material composition for theshell, the first material composition comprising the first material; anddetermine a second material composition for the integrally formedcomponent, the second material composition comprising the secondmaterial.

In some embodiments, the direct fabrication technique is an additivemanufacturing technique or a subtractive manufacturing technique. Theadditive manufacturing technique can comprise one or more of: vatphotopolymerization, material jetting, binder jetting, materialextrusion, powder bed fusion, sheet lamination, or directed energydeposition.

In some embodiments, the one or more integrally formed componentscomprise or are designed to substitute for an elastic, a wire, or aspring.

In some embodiments, the one or more integrally formed componentscomprise or are designed to substitute for an arch expander, a palatalexpander, or a palatal bar.

In some embodiments, the one or more integrally formed componentscomprise or are designed to substitute for a twin block, an occlusalblock, a bite ramp, an advancement structure, or a bite plate.

In some embodiments, the one or more integrally formed components areshaped to couple between a first portion and a second portion of theshell.

In some embodiments, the shell is shaped to be worn on a jaw of thepatient and the integrally formed component is shaped to couple to anappliance worn on an opposing jaw of the patient.

In some embodiments, the one or more integrally formed componentscomprise one or more mounting features shaped to couple to an auxiliarycomponent.

In another aspect, an appliance for repositioning teeth of a patient isprovided. The appliance can comprise: a shell forming a plurality ofcavities shaped to receive teeth of a mouth of the patient; and acomponent, wherein the component is integrally formed within the shell.

In some embodiments, the integrally formed component is configured tointeract with the same portion of the shell where the component isintegrally formed, or with another portion of the shell that isdifferent from the portion of the shell where the component isintegrally formed.

In some embodiments, the integrally formed component is configured tointeract with a shell, a tooth, a plurality of the patient's teeth, adental device, or an orthodontic device that is different from the shellwhere the component is integrally formed.

In some embodiments, the integrally formed component is directlyconnected to an orthodontic appliance.

In some embodiments, the integrally formed component is indirectlyconnected to an orthodontic appliance.

In some embodiments, the integrally formed component is directly orindirectly connected to another portion of the shell or directlyconnected to a portion of a different shell.

In some embodiments, the integrally formed component is a hook, abutton, an advancement structure, a guide path, or a protrusion.

In some embodiments, the integrally formed component is a window, achannel, a hole, or a recession.

In some embodiments, the integrally formed component is a mandibularadvancement structure, e.g., for treating sleep apnea.

In some embodiments, the integrally formed component is useful forrotating, tipping, translating, intruding, extruding, or torqueing thepatient's tooth.

In some embodiments, the integrally formed feature is useful forexpanding a patient's arch width, reducing open bite, or reducinggrinding of the patient's teeth.

In some embodiments, the integrally formed component comprises amounting feature shaped to engage an auxiliary component.

In some embodiments, the appliance is generated by a fabrication machineaccording to a set of fabrication instructions, the fabricationinstructions comprising the steps of: generating a digital model of theshell, the digital model including the feature integrally formed intothe shell, and; fabricating the shell having the feature integrallyformed into the shell.

In another aspect, a method for fabricating an appliance comprising anintegrally formed component is provided. The method can comprise:generating a digital model of the appliance, the digital modelcomprising a digital representation of a shell comprising a plurality ofteeth receiving cavities and a digital representation of a componentintegrally formed within the shell; and generating instructions forfabricating the appliance with the shell and integrally formed componentusing a direct fabrication technique, based on the digital model.

In some embodiments, the direct fabrication technique is an additivemanufacturing technique or a subtractive manufacturing technique. Theadditive manufacturing technique can comprise one or more of: vatphotopolymerization, material jetting, binder jetting, materialextrusion, powder bed fusion, sheet lamination, or directed energydeposition.

In some embodiments, the instructions are configured to control afabrication machine to form the component concurrently with the shell.

In another aspect, a method for fabricating an appliance comprising anintegrally formed component is provided. The method can comprise:determining a movement path to move one or more teeth from an initialarrangement to a target arrangement; determining an appliance geometrycomprising an integrally formed component for an orthodontic applianceconfigured to move the one or more teeth from the initial arrangement tothe target arrangement; and generating instructions for fabrication ofthe orthodontic appliance having the appliance geometry comprising theintegrally formed component.

In some embodiments, the method further comprises: determining a forcesystem to produce movement of the one or more teeth along the movementpath; and determining an appliance geometry comprising an integrallyformed component for an orthodontic appliance configured to produce theforce system.

FIG. 15 illustrates a tooth repositioning system 1500, in accordancewith embodiments. The tooth repositioning system 1500 includes anorthodontic appliance 1502 comprising a shell 1504 with an integrallyformed component 1506. The orthodontic appliance 1502 can be provided aspart of an orthodontic tooth repositioning system 1500. Any of theappliances described herein can be designed and/or provided as part of aset of a plurality of appliances used in a tooth repositioning system1500. The component 1506 may be integrally formed in any position withinthe shell 1504 of the appliance 1502 such the component 1506 isconfigured to enhance the patient's treatment plan. Placement of thecomponent 1506 within the shell 1504 may be designed as a part of thepatient's treatment plan so as to achieve the intermediate or finaltooth arrangement intended for the appliance 1502. For example, thetooth receiving system 1500 can include a first appliance 1502corresponding to an initial tooth arrangement with a first integrallyformed component 1506 within the shell 1504 of the appliance at a firstlocation, one or more intermediate appliances 1512 corresponding to oneor more intermediate arrangements having an intermediate integrallyformed component 1516 within the shell of the appliance, and a finalappliance 1522 with a final integrally formed component 1526 within theshell of the appliance corresponding to a target arrangement. Each ofthe appliances (the first appliance, any of the intermediate appliances,the final appliance) can comprise a corresponding integrally formedcomponent (e.g., first, intermediate, final), a plurality of integrallyformed components, or no integrally formed components. The integrallyformed component can be integrally formed within the shell of theappliance at a different location or at the same location as thepreceding appliance or as the subsequent appliance. While the componentsdepicted in FIG. 15 are of the same location, shape, and size,integrally formed components of the appliances of the system 1500 may beat any location of any appliance and can have any shape or any size, asdescribed herein and in accordance with the patient's treatment plan. Anexemplary, but not limiting, location of an integrally formed component1506, 1516 and 1526 is depicted in the appliances 1502, 1512 and 1522. Atarget tooth arrangement can be any planned resulting arrangement forthe patient's teeth that follows one or more incremental repositioningstages. Likewise, an initial tooth arrangement can be any initialarrangement for the patient's teeth that is followed by one or moreincremental repositioning stages.

Any appliance for use at one or more of the incremental repositioningstages of the tooth repositioning system may include an integrallyformed component. A method for designing a tooth repositioning systemincludes, but is not limited to, planning a placement of the integrallyformed component within any of the appliances of the tooth repositioningsystem used during one or more of the incremental repositioning stages,planning the number of appliances to comprise an integrally formedcomponent for use during one or more of the incremental repositioningstages, planning the order of use of appliances comprising an integrallyformed components, and the like.

Various types of integrally formed components are suitable forincorporation with the appliances described herein. An integrally formedcomponent may have any of a plurality of geometries, including shapes,dimensions, angles, and the like. Shapes of an integrally formedcomponent can include, but are not limited to, a circle, an oval, anellipse, a curved structure with a complex shape, a triangle, a square,a rectangle, a triangle, a polygon, a pentagon, a hexagon, a heptagon,and the like. The integrally formed component may have walls which arestraight or curved. The walls of the integrally formed component mayform angles with each other, or may smoothly transition into each other(e.g., via a curved join surface).

The position and/or orientation of an integrally formed component can bevaried as desired. For example, a position of the component can include,but is not limited to, a lingual surface of the appliance, an occlusalsurface of the appliance, a buccal surface of the appliance, a gingivalportion of the appliance, an interior surface of the appliance (e.g.,near the received teeth), an exterior surface of the appliance (e.g.,away from the received teeth), an anterior portion of the appliance, aposterior portion of the appliance, a distal portion of the appliance, amesial portion of the appliance, or the like, or combinations thereof.The component can be oriented away from or towards one or more of thefollowing: a lingual surface of the appliance, an occlusal surface ofthe appliance, a buccal surface of the appliance, a gingival portion ofthe appliance, an interior surface of the appliance (e.g., near thereceived teeth), an exterior surface of the appliance (e.g., away fromthe received teeth), an anterior portion of the appliance, a posteriorportion of the appliance, a distal portion of the appliance, a mesialportion of the appliance, or the like, or combinations thereof.

An integrally formed component may be located in a single plane (e.g.,x-plane, y-plane, z-plane) of the appliance, or may be located in aplurality of planes in the appliance. Optionally, the integrally formedcomponent may project from one or more planes in the appliance and/orrecess through one or more planes in the appliance. In some embodiments,the component can be contained wholly within the interior of theappliance such that no portion is directly exposed to the intraoralenvironment (e.g., a slit, a channel, a recess, a hole or the like or asdescribed herein). In some embodiments, the component can be partiallyor not contained within the interior of the appliance such that one ormore portions are directly exposed to the intraoral environment (e.g., ahook, a button, a bevel, a ridge, an edge, a flap, a block or the likeor as described herein). The location of the integrally formed componentmay be determined during treatment planning, during fabrication, or aspart of any other method described herein. In some embodiments, theplacement of the integrally formed component depends upon the materialfrom which the component is formed, such materials as discussed hereinor known to one of ordinary skill in the art.

In some embodiments, the integrally formed component is located at oneor more of a plurality of positions within an appliance shell. Theplurality of positions may include one or more of: a lingual surface, anocclusal surface, a buccal surface, a gingival portion, an interiorsurface (e.g., near the received teeth), an exterior surface (e.g., awayfrom the received teeth), an anterior portion, a posterior portion, adistal portion, a mesial portion, or the like, or combinations thereof.In some embodiments, an appliance shell includes one or more wallsdefining teeth-receiving cavities (occlusal, buccal, and/or lingualwalls) and the component can be formed partially or wholly within thewall(s) and/or lie on a single shared plane as the wall(s). Theintegrally formed component may be positioned such that the longest axisof the integrally formed component aligns with or does not align withthe mesial-distal axis, posterior-anterior axis, and/or vertical axis ofthe shell. Alternatively, the integrally formed feature may bepositioned such that the longest axis of the integrally formed featuredoes not align with the mesial-distal axis, posterior-anterior axis,and/or vertical axis of the shell. In some embodiments, an integrallyformed component in an appliance shell can be positioned to engage atarget (e.g., a tooth, another intraoral appliance) in order to affectforce applied by the appliance to the target.

The dimensions (e.g., length, width, height, surface area, volume, etc.)of an integrally formed component can be configured as desired. In someembodiments, the dimensions are selected based on one or more of thefollowing: the shape of the integrally formed component, the use of theintegrally formed component in the patient's treatment plan, thedimensions of the patient's mouth, and/or the dimensions of otherappliances or intraoral devices located in the patient's mouth.

The material composition of an integrally formed component may be thesame as the rest of the appliance (e.g., the appliance shell), or may bedifferent from the rest of the appliance. For example, in someembodiments, an appliance shell is directly fabricated from a firstmaterial, and an integrally formed component is fabricated from asecond, different material. The first material can differ from thesecond material with respect to any of the properties described herein,including but not limited to stiffness, elastic modulus, hardness,thickness, strength, compressibility, stress relaxation, hydrophobicity,hydrophilicity, Poisson ratio, strain rate, viscoelasticity, and/orpolarity. Direct fabrication of an orthodontic appliance including ashell produced from a first material and an integrally formed componentproduced from a second, different material can be performed according tothe methods described further herein.

In some embodiments, an integrally formed component is used to addstrength and/or additional force to an appliance. The integrally formedcomponent can be a reinforcement structure (e.g., a corrugation)arranged to stiffen the appliance against deflection. For example, acorrugation can be used to stiffen the gingival edge of an orthodonticappliance against lateral deflection induced, for example, by the forcefrom a coupled elastic. In some embodiments, the integrally formedreinforcement structure is positioned to apply additional force to oneor more teeth received by the appliance. The integrally formedreinforcement structure can be located such that the force is appliedalong a desired direction. An orthodontic appliance can have areinforcing structure formed in one or more of a gingival edge, buccalsurface, lingual surface, occlusal surface, interior surface, orexterior surface of the appliance. The reinforcing structure can beintegrally formed with the shell by direct fabrication of the appliance,as described herein.

FIG. 16 illustrates an orthodontic appliance 1600 with an integrallyformed reinforcing structure, in accordance with embodiments. Asillustrated in FIG. 16 , a corrugation 1602 is integrally formed into anappliance shell 1604 to provide additional strength, tensile force, orthe like to a portion of the teeth positioned within the tooth receivingcavities of the shell 1604. The integrally formed corrugation can belocated so as to apply force to the teeth in the desired direction. Thelocation, length, thickness, and amount of corrugation used may bevaried throughout the embodiments described herein.

Although components formed by addition of material to toothrepositioning appliances may perform useful functions in orthodontictreatment, in some embodiments, it may also be beneficial to formcomponents by removing material in an appliance, e.g., in order to formhollow portions or windows. For example, hollow portions may be formedin one or more walls of an appliance shell in order to reduce weight ofthe appliance (e.g., may be beneficial for patients with sensitivitiesto the appliances) and to reduce the cost of the appliance. The size andgeometry of the hollow portion can be varied as desired in order toachieve weight reduction while maintaining strength. Optionally,internal support structures may be added to the hollow areas to addstrength such as struts or the like which provide additional support tothe surrounding portions of the shell wall around the hollow portion.Support structures can be of any size, geometry, angle or location asdescribed herein. The support structures can increase the strengthand/or stiffness of the appliance. An appliance with integrally formedhollow portions and/or support structure can be produced by directfabrication, as described herein.

FIG. 17 illustrates an orthodontic appliance 1700 with integrally formedhollow portions, in accordance with embodiments. The appliance 1700 mayhave a shell 1702 defining one or more tooth receiving cavities, and oneor more hollow portions 1704, 1706 can be formed in the shell wall,e.g., to reduce weight of the appliance 1700. Optionally, internalsupport structures 1708 such as struts or the like may be integrallyformed within the hollow portions (e.g., hollow portion 1706) to addstrength and provide additional support to the surrounding portions ofthe shell wall around the hollow portion.

In some embodiments, an appliance can be integrally formed with one ormore apertures (e.g., windows) to expose at least a portion of areceived tooth or teeth. Such apertures may be formed by omitting orremoving portions of the wall of the appliance shell. In suchembodiments, when the shell is positioned over the patient's teeth,portions of the teeth beneath the apertures may be exposed, such asocclusal surfaces, buccal surfaces and/or lingual surfaces. Exposingsuch tooth surfaces may allow brackets, buttons or other orthodonticcomponents to be utilized in conjunction with the appliance, forexample. Advantageously, exposure of the occlusal surfaces in anappropriate size and location may allow for the natural interdigitationof the upper and lower teeth to be maintained during treatment, forexample. This may also be achieved with the presence of one or morelarger apertures over portions of the occlusal surfaces of the teeth. Insuch embodiments, segments of the shell may or may not be present acrossthe interproximal regions or spaces between the teeth. In suchembodiments, interdigitation of at least portions of the upper and lowerteeth may benefit tooth and jaw orientations, leading to improvedtreatment, appearance, comfort, and consequently patient compliance.Similarly, use of apertures on occlusal surfaces may prevent open biteand may reduce wear and/or abrasion of portions of the appliance and/orportions of the patient's tooth and/or teeth. Likewise, similarly placedapertures may provide the benefits offered by a lower elastic modulus,such that the reduced stiffness may be provided by the absence of thematerial.

In some embodiments, an integrally formed component is designed toinclude or substitute for an auxiliary component that would otherwise becoupled to the orthodontic appliance. As discussed above and herein, anintegrally formed component can include or be designed to substitute forone or more of the following auxiliary components: elastics, wires,springs, bars, arch expanders, palatal expanders, twin blocks, occlusalblocks, bite ramps, mandibular advancement splints, bite plates,pontics, hooks, brackets, headgear tubes, springs, bumper tubes, palatalbars, frameworks, pin-and-tube apparatuses, buccal shields, buccinatorbows, wire shields, lingual flanges and pads, lip pads or bumpers,protrusions, divots, or any other structure or feature suitable for usein conjunction with the appliances herein to treat a patient.

For example, the appliances herein can include integrally formedcomponents configured for treating sleep apnea (e.g., obstructive sleepapnea (OSA)) in a patient by displacing the lower jaw (mandible) of thepatient anteriorly relative to the upper jaw (maxilla), also known as“mandibular advancement.” For example, an appliance can compriseintegrally formed occlusal structures (e.g., advancement structures,twin blocks, etc.), which can be configured such that theanterior-posterior force exerted on the teeth by the appliance duringmandibular advancement does not cause tooth repositioning or does notexceed a predetermined amount of force, e.g., an amount that would causetooth repositioning and/or patient discomfort.

Often, appliances for treating sleep apnea are designed to be worn onthe upper and lower jaws. In some embodiments, the appliance fortreating sleep apnea in a patient comprises an appliance shellcomprising a plurality of cavities shaped to receive teeth of a jaw ofthe patient and an integrally formed advancement structure arranged tointeract with an opposing jaw of the patient so as to displace the lowerjaw anteriorly relative to the upper jaw. The appliances describedherein can further comprise a second appliance shell comprising a secondplurality of cavities shaped to receive teeth of the opposing jaw. Theadvancement structure can interact with the opposing jaw via engagementwith a second advancement structure of the second appliance shell. Forexample, the advancement structure comprises a first protrusionextending from the appliance shell and having a first engagementsurface, and the second advancement structure comprises a secondprotrusion extending from the second appliance shell and having a secondengagement surface configured to engage the first engagement surface.The first protrusion can be shaped to mate with the second protrusion.An inclination angle of the first and second engagement surfaces can bedetermined based on one or more of anatomy of the patient's jaw,kinematic data of the patient's jaw, or a targeted distance for thedisplacement. In some embodiments, the advancement structure comprises afirst coupling element and the second advancement structure comprises asecond coupling element, the first and second coupling elementsconfigured to interact with each other so as to reversibly bias theadvancement structure and second advancement structure towardpredetermined relative positions. The first and second coupling elementscan comprise magnetic elements, elastic tethers, mating features, orcombinations thereof, for instance.

FIG. 18 illustrates an appliance 1800 with an integrally formed occlusalstructure 1802 on the occlusal surface of the appliance shell 1804, inaccordance with embodiments. The geometry and positioning of theocclusal structure 1802 can be configured according to the particularfunctionality of the appliance 1800. For example, the occlusal structure1802 can be shaped and positioned to serve as a twin block, occlusalblock, bite ramp, or advancement structure. In some embodiments, theocclusal structure 1802 is shaped to engage a complementary structure onan appliance worn on the patient's opposing jaw in order to adjust thepatient's bite, e.g., along an anterior-posterior direction and/orleft-right direction. Optionally, the occlusal structure 1802 canincludes features matching the features of the patient's occlusalsurfaces, e.g., occlusal features of the opposing arch. In someembodiments, the built-in occlusal structure 1802 is formed from adifferent material than the shell 1804 using the direct fabricationapproaches herein. For example, the occlusal structure 1802 can beformed from a stiffer material than the shell 1804 in order to provideimproved durability against bruxing.

FIG. 19 illustrates an appliance 1900 with an integrally formed archexpander 1902 on the lingual surface of the appliance shell 1904, inaccordance with embodiments. The arch expander 1902 can be coupled tothe posterior portions of the shell 1904 in a position spanning thepatient's palate in order to exert forces along a buccal direction toexpand the patient's arch. The arch expander 1902 may be placed into acompressed configuration when the appliance 1900 is worn by the patientin order to produce the arch expansion forces. In some embodiments, thebuilt-in arch expander 1902 is formed from a different material than theshell 1904 using the direct fabrication approaches herein. For example,the arch expander 1902 can be fabricated from a relatively stiff and/orexpandable material in order to produce buccally-directed forces forexpanding the width of the patient's arch.

FIG. 20 illustrates an appliance 2000 with an integrally formed flowstructure 2002 on an upper shell 2004 and a lower shell 2006, inaccordance with embodiments. The air flow structure 2002 can be coupledto the occlusal surfaces of the upper shell 2004 and lower shell 2006such that the structure 2002 is positioned between the patient's upperand lower arches when the appliance 2000 is worn. The air flow structure2002 includes a passage 2008 extending through the interior of thestructure 2002 along an anterior-posterior direction in order to providean unobstructed conduit for air flow through the appliance 2000 (see,e.g., arrows 2010). The passage 2008 can be shaped to promote easierbreathing when the appliance is worn, e.g., using computational fluiddynamics to model air flow. The direct fabrication approaches providedherein enable precise control over the geometry of the built-in air flowstructure 2002, thus improving the extent to which fluid dynamicscharacteristics of the appliance 2000 can be customized and optimized.In some embodiments, the appliance 2000 can be used as a mouth guard toprotect the received teeth from trauma while permitting mouth breathingthrough the air flow structure 2002. In such embodiments, the uppershell 2004, lower shell 2006, and/or air flow structure 2002 can beformed from relatively soft or elastic materials that serve as paddingto protect the patient's teeth.

FIG. 21 illustrates an appliance 2100 with an integrally formed pontic2102 in the appliance shell 2104, in accordance with embodiments. Thepontic 2102 can be provided to replace one or more missing teeth, e.g.,in order to improve the aesthetic appearance of the patient's dentition,as well as to maintain spaces between teeth during treatment. Using thedirect fabrication techniques disclosed herein, the pontic 2102 can beintegrally formed as a single piece with the shell 2104 using a suitablycolored material. The pontic 2102 can be produced by filling a cavity ofthe shell 2104 with a pontic material, for example. Alternatively, thepontic 2102 can be produced by applying a material to an interior and/orexterior surface of the appliance 2104 in order to create the appearanceof a natural tooth. This approach eliminates additional processing stepsto fill the shell 2104 with a pontic material or couple a discretepontic structure, thus simplifying the manufacturing process.

Optionally, an integrally formed component can be an ornamental feature,such as coloring or patterning of an appliance. For example, the directfabrication approaches can be used to produce appliances with integrallyformed ornamental features such as colors, decorative geometries,patterning, embossing, etc., rather than requiring that such ornamentalfeatures be added to the appliance in a separate post-processing step.The approaches herein are can be used to produce appliances withpatient-customized ornamental features, for example. In someembodiments, software is provided to allow patients to create customizedornamental features.

In some embodiments, an appliance includes an integrally formedinflatable structure such as a bladder or balloon in the applianceshell. The inflatable structure can be formed from a relatively elasticmaterial so as to permit expansion of the inflatable structure whenfilled with a fluid (e.g., a gas or liquid). The inflatable structurecan be positioned at a location on the appliance shell where increasedstrength and/or stiffness is desired, e.g., to increase an amount offorce applied to the teeth at or near the location. The inflatablestructure can be inflated with fluid prior to placement or afterplacement of the appliance on the patient's teeth, as desired. The fluidpressure within the inflatable structure can be varied in order toachieve a targeted amount of strength and/or stiffness. Optionally, thefluid pressure can be adjusted during treatment in order to providevarying amounts of force application onto teeth.

In some embodiments, an appliance includes a built-in layer or coatingintegrally formed with the appliance shell by direct fabrication. Thelayer or coating can be located on one or more of a buccal surface,lingual surface, occlusal surface, exterior surface, and/or interiorsurface of the shell. The layer or coating can be formed from one ormore materials configured to provide additional functionality to theappliance. For example, the layer or coating can be formed from amoisture resistant material, e.g., in order to act as a sealant toreduce stress relaxation of the appliance associated with waterabsorption. As another example, the layer or coating can be formed froma material that resists or reduces staining. In another example, thelayer or coating can be used to reduce friction between the appliance,the patient's teeth and/or another device. In some embodiments, aprotective layer or coating is integrally formed into the occlusalsurfaces of an appliance to protect the appliance, the patient's teeth,and/or another device, e.g., from grinding, pressure, and interference.In yet another example, the layer or coating can incorporate therapeuticagents or functional agents for drug delivery, flavoring, etc. Thedirect fabrication methods herein allow such layers or coatings to beformed with the shell in a single processing step.

In some embodiments, an integrally formed component may form a spring inthe shell of an appliance for use in transmitting repositioning force toone or more teeth, e.g., to reposition teeth from a first arrangement toa successive arrangement. A spring of this type may be of a traditionaldesign or it may be specially designed for use with polymeric shellappliances. Further, it may be specially designed to engage anattachment device mounted on a tooth, which is a device primarilyutilized in conjunction with removable shell appliances. In someembodiments, the spring can be comprised of a pre-formed strip orportion of the shell which engages an attachment device mounted on anunderlying tooth. The attachment device can be accessible through awindow in the appliance as described herein. A full description ofexemplary attachment devices is described in PCT Publication No. WO00/32132, which corresponds to application Ser. No. 09/454,278, assignedto the assignee of the present invention. Both documents areincorporated herein by reference in their entirety for all purposes.

In some embodiments, the integrally formed component can be a largerprotrusion useful to provide additional support for the appliance and/orto provide orthodontic functions. Such a protrusion may form a palatalbar. A variety of palatal bars may be formed in the shell, such as a lowhanging transpalatal bar for control of vertical dimension. These mayprovide orthodontic functions similar to conventional palatal bars, andmay also provide support for the appliance. This may be particularlyuseful in highly flexible appliances. The protrusion may be a corrugatedpalatal bar, e.g., for increased strength and support.

In some embodiments, the integrally formed component may serve as a biteplate. A bite plate is a device which prevents the teeth from closingcompletely. The resulting open state, or disclusion, may be useful for anumber of orthodontic treatments, including crossbite correction andcontrolled passive eruption. To provide anterior disclusion, anappliance may have an increase in thickness of material in the posteriorocclusion regions of the shell, as previously discussed. The increase inthickness of material may be applied to the appliance or formed by theappliance to create a protrusion over the designated occluding surfaces.Similarly, posterior disclusions may be provided by forming a protrusionin the shell which extends at least a portion of an upper palatal regionwith added thickness, as previously discussed.

In some embodiments, an orthodontic appliance includes an integrallyformed component shaped to engage (e.g., receive, couple to, connectwith, mate with a complementary shape of, etc.) another portion of thesame appliance. For example, an integrally formed component can belocated at a first portion (e.g., a buccal portion, a lingual portion,an occlusal portion, a gingival portion, an anterior portion, and/or aposterior portion) of the appliance and can be configured to engage witha second portion (e.g., a buccal portion, a lingual portion, an occlusalportion, a gingival portion, an anterior portion, and/or a posteriorportion) of the same appliance. In some embodiments, an integrallyformed component used to couple between multiple portions of a singleappliance is an elastic, spring, telescoping element, or the like.

FIG. 22 illustrates an orthodontic appliance 2200 with an integrallyformed component that couples to another portion of the appliance, inaccordance with embodiments. In the depicted embodiment, a telescopingelement 2202 is integrally formed into the appliance shell 2204. Thetelescoping element 2202 includes a piston 2206 and a recess 2208 shapedto receive and coupled to the piston 2206. By adjusting the length ofthe piston 2206 received within the recess 2208, the telescoping element2202 can be used to generate variable amounts of force applied to theteeth received by the appliance shell 2204. Optionally, the recess 2208can include a plurality of holes 2210 formed in the walls of the recess2208 and shaped to receive a stop bracket 2212. The stop bracket 2212can be configured to be positioned and re-positioned throughout thecourse of treatment in order to adjust the amount of force applied tothe patient's jaw by the telescoping element 2202.

In some embodiments, an orthodontic appliance includes an integrallyformed component shaped to engage another device. The additional devicecan be a pin, a button, a screw, an elastic, or an orthodonticappliance, such as a second orthodontic appliance worn by the patient.The additional device can be connected to a tooth, the patient's jaw, aportion of the same appliance, a portion of another appliance, a portionof another integrally formed component of the same appliance, a portionof another integrally formed component of another appliance, and/or aportion of any other orthodontic device in the patient's mouth. Forexample, a first orthodontic appliance worn on the patient's upper orlower jaw can include an integrally formed component that engages (e.g.,couples to) a second orthodontic appliance worn on the patient'sopposing jaw. In some embodiments, an integrally formed component canengage with the patient's tooth and/or teeth or a portion thereof, withanother appliance or a portion thereof, or the like. Such integrallyformed components can be used to increase an amount of force applied tothe teeth, decrease an amount of force applied to the teeth, or changethe distribution of force applied to the teeth, relative to theappliance in the absence of such components.

As another example, an orthodontic appliance can include an integrallyformed component (e.g., an aperture or receptacle) that engages a deviceattached to a patient's tooth or teeth (e.g., a tooth-mounted attachmentdevice) or otherwise located in the patient's intraoral cavity (e.g., atemporary anchoring device (TAD)). For instance, the integrally formedcomponent can be configured to couple to a TAD or other intraoral deviceprovided in the patient's mouth. The intraoral device may or may not becoupled to a surface of the patient's teeth. In some embodiments, theintraoral device may be, but is not limited to, a retraction screwinserted through the gingival tissue and embedded into a bone of thepatient's mouth. The intraoral device (e.g., a TAD) may be embedded intoany suitable bone at any suitable location in the patient's mouth,including either buccal and/or lingual facing bone surfaces.

In some embodiments, an integrally formed component may further includestructures (e.g., holes, slits, buttons, recesses, etc.) shaped todirectly connect to another device, such as by snap fit and/orinterference fit, for example. As used herein, “directly connect” mayrefer to the integrally formed component coupling to the other devicewithout using an intermediary connecting or fastening element, such asan elastic, a wire, a pin, a screw, a spring, adhesive, or the like.Alternatively, the integrally formed component may indirectly connectwith the other device. As used herein, “indirectly connect” may refer tothe integrally formed component coupling to the other device using anintermediary connecting or fastening element, such as an elastic, awire, a pin, a screw, a spring, adhesive, or the like.

FIG. 23 illustrates an orthodontic system 2300 with an integrally formedcomponent (e.g., elastic 2302) that couples an upper appliance 2304 wornon the upper jaw and a lower appliance 2306 worn on the lower jaw, inaccordance with embodiments. The elastic 2302 can be to be integrallyformed as a single piece with the appliance 2304, 2306 using the directfabrication techniques described herein. In the depicted embodiment, theelastic 2302 is coupled to the upper appliance 2304 at a first couplingpoint 2308 and is coupled to the lower appliance 2306 at a secondcoupling point 2310. The first coupling point 2308 can be positionedanteriorly relative to the second coupling point 2310 in order toadvance the lower jaw anteriorly relative to the upper jaw, e.g., fortreating class II malocclusions, sleep apnea, etc. In alternativeembodiments, the first coupling point 2308 can be positioned posteriorlyrelative to the second coupling point 2310 in order to retract the lowerjaw relative to the upper jaw, e.g., for treating class IIImalocclusions. The use of built-in elastics can be advantageous forimproving convenience and patient compliance, by allowing the patient toinsert the appliances directly without having to install, remove, and/orchange out elastics.

FIG. 24 illustrates an orthodontic appliance 2400 with an integrallyformed component that couples to a device coupled to an intraoralstructure, in accordance with embodiments. The appliance 2400 includes ashell 2402 having cavities for receiving a patient's teeth and anintegrally formed component, depicted herein as a protrusion 2404 havinga hole 2406 shaped to receive and couple to a device 2408 (e.g., anattachment device, anchoring device such as a TAD, screw, etc.) coupledto an intraoral structure 2410 (e.g., a tooth). The protrusion 2404 canbe rigid or elastic and may be used to extrude teeth or control overand/or under bite, for example. In alternatively embodiments, theintegrally formed component can include other types of structures tomount onto the device 2408. For example, the integrally formed componentcan be a protrusion, a paddle, a flap, a tab, or the like that isdirectly or indirectly connected to the device 2408. Different types ofintegrally formed components can be used to allow for different ways ofcoupling to teeth, for example, to intrude teeth rather than to extrudeteeth. Likewise, the device 2408 is depicted herein as an attachmentdevice mounted to a tooth on the opposing jaw, but other types ofdevices and configurations can also be used. For example, the device2408 can be integrally formed with a second orthodontic appliance or aportion of the appliance shell 2402, or can be attached to a differentintraoral structure, such as the patient's jawbone or palate, forexample.

In some embodiments, an orthodontic appliance includes an integrallyformed component shaped to provide one or more mounting features forcoupling an auxiliary component to the appliance. For example, theintegrally formed component includes a mounting feature for coupling theappliance to an expander, archwires, or other like devices or elementsof devices often useful for expanding the width of a patient's archduring the course of treatment for a condition, such as sleep apnea Theauxiliary component can be any structure or device configured to be usedin combination with an appliance in order to perform a function, such asone or more of force application and/or modification, structuralreinforcement, actuation, sensing, providing power, and so on. Theauxiliary component can be any device useful for orthodontic or dentaltreatment of a patient, such as elastics, wires, springs, bars, archexpanders, palatal expanders, twin blocks, occlusal blocks, bite ramps,mandibular advancement splints, bite plates, pontics, hooks, brackets,headgear tubes, springs, bumper tubes, palatal bars, frameworks,pin-and-tube apparatuses, buccal shields, buccinator bows, wire shields,lingual flanges and pads, lip pads or bumpers, protrusions, divots,batteries, or sensors.

A mounting feature can be any structure or component that engages anauxiliary component or a portion thereof in order to couple the deviceto the orthodontic appliance. The mounting feature can be shaped so asto couple to, connect to, receive, engage and/or partially or whollyencapsulate the auxiliary component. For example, a mounting feature caninclude a hole, aperture, slit, groove, hook, button, ridge, flap,channel, etc. shaped to engage a portion of the auxiliary component soas to couple the appliance thereto. As another example, a mountingfeature can include a cavity, chamber, receptacle, recess, opening,window, etc. shaped to receive a portion of the auxiliary component soas to partially or wholly encapsulate the auxiliary component within theappliance. The location of the mounting feature can correspond to thedesired location of the auxiliary component relative to the applianceshell. An auxiliary component can be positioned at any location on theappliance shell, such as a lingual surface, occlusal surface, buccalsurface, gingival portion, interior surface (e.g., near the receivedteeth), exterior surface (e.g., away from the received teeth), anteriorportion, posterior portion, distal portion, mesial portion or the like,or combinations thereof. The location of the auxiliary component can bedetermined based on the function of the auxiliary component. Forinstance, a sensor configured to measure bite force can be located on anocclusal surface. A sensor configured to measure pressure, humidity,and/or temperature can be located on a buccal surface (e.g., near theposterior teeth for improved aesthetics) or on a lingual surface.

As discussed above and herein, the direct fabrication methods of thepresent disclosure allow for improved production of appliances withintegrally formed mounting features for coupling to an auxiliarycomponent. Using direct fabrication, mounting features can be integrallyformed at any location on the appliance to accommodate coupling of anauxiliary component. In some embodiments, the auxiliary component can beformed and/or coupled to the appliance concurrently with formation ofthe appliance, e.g., using the same fabrication machine and/or process.For example, an auxiliary component can be automatically positioned andmounted to the mounting feature (e.g., using robotic mechanisms and thelike) while the appliance is being formed using the direct fabricationmethods herein, similar to insert molding techniques. Alternatively, theauxiliary component can be positioned and mounted to the mountingfeature after the appliance has been formed.

In some embodiments, an integrally formed component includes a mountingfeature configured to engage with (e.g., couple to) a connectingelement, such as an elastic. Use of dental elastics can change theforces applied across a patient's tooth and/or teeth. The mountingfeature can hold the elastic in place relative to the appliance when theelastic is properly inserted and positioned. The mounting feature may bea protrusion from or a recession of the appliance to engage with anelastic. Such protrusions or recessions may be but are not limited tohooks, buttons, knobs, pegs, flaps, protrusions, channels, grooves,ridges, slits, or divots.

For example, an appliance may have an integrally formed mounting featurein the wall of the appliance shell in the form of a hook for mountingelastics such as flexible bands, ligatures, or adjunct devices. Such ahook may resemble hooks found in dental care, or it may be speciallydesigned for use with shell appliances. In some embodiments, an elasticcan be coupled with the appliance via a hook formed by creating au-shaped aperture located in the side of the appliance. The aperture canbe formed into an existing appliance at a location selected for thetransfer of the force from the elastic into the appliance. The aperturecan have a slot width and a shape selected to accommodate the elastic. Ahook can also be positioned along a gingival margin of the appliance.For example, the tip of the hook may curve or angle away from softtissue or back toward the tooth surface. The tip of the hook may also becurved, angled, or bent towards the gingival line such that the elasticmay be placed into the appliance first before the appliance is worn, andthe hook angle/curvature keeps the elastic from falling off of theappliance. An integrally formed hook may have any suitable shape forreceiving an elastic, including any of those discussed in U.S. patentapplication Ser. No. 12/722,130, entitled “REINFORCED ALIGNER HOOKS,”which is commonly assigned and incorporated by reference herein in itsentirety for all purposes.

In some embodiments, the appliance can have more than one integrallyformed mounting feature, such as a cutout and a hook. For example, thecutout and the hook may be provided for different teeth on differentjaws so that coupling of an elastic may operate to apply tooth/jawrepositioning forces sufficient to treat tooth malocclusions such asdistocclusion or mesiocclusion. A cutout may be provided for disposalover a posterior tooth in one jaw, while a hook may be provided fordisposal over an anterior tooth in another jaw, for instance.

FIG. 25 illustrates an orthodontic appliance 2500 with integrally formedmounting features for coupling an elastic 2502, in accordance withembodiments. The appliance 2500 comprises a shell 2504 with a first(e.g., anterior) integrally formed mounting feature, such as a hook2506, and a second (e.g., posterior) integrally formed mounting feature,such as a hook 2508, can be configured to be coupled to a dental elastic2502. The elastic 2502 can exert a tensile force against differentportions of the appliance 2500 (e.g., anterior and posterior portions)that are transmitted to the underlying teeth. It shall be appreciatedthat the placement and geometries of the integrally formed mountingfeatures shown in FIG. 25 are exemplary and not intended to limit theplurality of placements and geometries possible in accordance with theaspects and embodiments described herein. Accordingly, the integrallyformed mounted features can be integrally formed within the shell 2504of the appliance 2500 at a different location or at the same location asthe preceding appliance or as the subsequent appliance. The integrallyformed mounting feature may be at any location of any appliance inaccordance with the patient's treatment plan.

FIG. 26 illustrates an orthodontic system 2600 including an upperappliance 2602 with an integrally formed upper mounting feature 2604 anda lower appliance 2606 with an integrally formed lower mounting feature2608 for coupling an elastic 2610, in accordance with embodiments. Inthe depicted embodiment, the upper mounting feature 2604 is a first hookintegrally formed into the upper appliance 2602 worn on the upper jawand the lower mounting feature 2608 is a second hook integrally formedinto a lower appliance 2606 on the lower jaw. A dental elastic 2610 canbe positioned over each hook to connect the upper appliance 2602 andlower appliance 2606, for example, to apply force to change theanterior-posterior alignment of the top jaw relative to the bottom jawof the patient. The location and geometries of the upper and lowermounting features depicted herein are exemplary and not limiting.Rather, the upper and lower mounting feature can have any geometryand/or location as described herein.

Optionally, the appliance can be further modified to accommodate aportion of a coupled elastic or other connecting element coupled to anintegrally formed mounting feature. For example, the appliance caninclude a cutout or recess shaped to avoid physical and/or functionalinterference with an elastic. The cutout can have any shape appropriatefor preventing interference for use with a plurality of patienttreatment plans including, for example, for treatment of distocclusionor mesiocclusion, or facilitating extrusion, intrusion, rotation,tipping and/or torqueing. Accordingly, in some embodiments, coupling anelastic to a portion of the shell comprising a cutout or recess mayoperate to apply tooth and/or jaw repositioning forces sufficient tointrude or extrude a tooth. For example, a cutout may be provided fordisposal over a tooth, while two hooks may be provided for disposal overboth lateral sides of the same tooth. Accordingly, an elastic mayoperate to apply tooth/jaw repositioning forces that tend to move one ormore teeth or the jaw in a vertical direction to intrude or extrude atooth, for example.

FIG. 27 illustrates an orthodontic appliance 2700 including a cutout2702 for accommodating a coupled elastic 2704, in accordance withembodiments. The appliance 2700 includes a shell with a cutout 2702 overthe occlusal surface of a received tooth, such that the occlusal surfaceof the tooth is exposed. The shell includes a first integrally formedmounting feature (e.g., a protrusion 2706) and a second integrallymounting feature (e.g., a protrusion 2708). Each of the protrusions2706, 2708 can comprise a hole configured to receive and couple anelastic 2704. The mounting features can be located on opposite sides ofthe appliance 2700 (e.g., buccal and lingual surfaces), such that thecoupled elastic 2704 is configured to push down on the occlusal surfaceof the tooth to intrude the tooth. Alternatively, the elastic 2704 canpull up on the occlusal surface (e.g., via attachment mounted on thetooth) to extrude the tooth (not shown).

FIG. 28 illustrates an orthodontic appliance 2800 including a cutout2802 for accommodating a coupled elastic 2804, in accordance withembodiments. Similar to the appliance 2700, the appliance 2800 includesa shell with a cutout 2802 over the occlusal surface of a receivedtooth, such that the occlusal surface of the tooth is exposed. The shellincludes a first integrally formed mounting feature (e.g., a hook 2806)and a second integrally mounting feature (e.g., a hook 2808). Each ofthe hooks 2806, 2808 can be shaped to receive and couple an elastic2804. The mounting features can be located on opposite sides of theappliance 2800 (e.g., buccal and lingual surfaces), such that thecoupled elastic 2804 is configured to push down on the occlusal surfaceof the tooth to intrude the tooth. Alternatively, the elastic 2804 canpull up on the occlusal surface (e.g., via attachment mounted on thetooth) to extrude the tooth (not shown).

The illustrations in FIGS. 27 and 28 are not intended to be limiting, asintegrally formed mounting features may have different geometries,locations and/or can be configured to treat a single tooth or aplurality of teeth. Additionally, an elastic can be coupled to a tooth,a different portion of the same appliance, or a different portion of adifferent device, as prescribed by the patient's treatment plan.

FIG. 29 illustrates an orthodontic appliance 2900 including integrallyformed mounting features for coupling a spring 2902, in accordance withembodiments. The appliance 2900 includes a shell 2904 comprising twointegrally formed mounting features. A first mounting feature 2906 ispositioned on a first distal portion of the shell 2904 and is shaped tocouple a first portion of the spring 2902 (or a wire, or the like). Asecond mounting feature 2908 is positioned on a second distal portionopposite the first distal portion and is shaped to couple a secondportion of the spring 2902 (or a wire, or the like). The first andsecond mounting features 2906, 2908 can be used to couple to a spring2902 for use in spreading a patient's arch and/or palate, for example,as a stage of a patient's treatment plan to treat sleep apnea.Accordingly, the features may be configured to engage a plurality ofdifferent types of springs to allow arch and/or palate expansion forcesto be adjusted during treatment. For example, different springs ofdifferent tensions can be used during the various stages during thecourse of treatment.

FIG. 30 illustrates an orthodontic appliance 3000 including integrallyformed mounting features for coupling an advancement structure 3002, inaccordance with embodiments.

The appliance 3000 includes a shell 3004 with a plurality of integrallyformed mounting features (e.g., protrusions 3006, 3008) shaped to matewith a corresponding mounting interface (e.g., holes 3010, 3012) in theadvancement structure 3002. In alternative combinations, the mountingfeatures can be located on the advancement structure 3002 and themounting interface can be integrally formed with the shell 3004. Themounting features of the shell 3004 can be a pin, a peg or the like, andis typically a protrusion. In some embodiments, the plurality of holesin the advancement structure 3002 is greater than the number ofcorresponding protrusions of the shell 3004, such that the advancementstructure 3002 can be positioned and re-positioned on the same appliancein accordance with the patient's treatment plan during the course oftreatment in a plurality of different locations. Additionally, aplurality of advancement structures with different geometries can beused with the same shell by replacing an existing advancement structurewith a different advancement structure. The illustrations are notintended to be limited as integrally formed features may have differentgeometries, locations and/or can be configured in accordance with apatient's treatment plan. A full description of an exemplary orthodonticappliance with advancement structures is described in U.S. applicationSer. No. 14/992,325, the disclosure of which is incorporated herein byreference in its entirety.

Optionally, the appliance can include a reinforcement structure in thevicinity of the integrally formed mounting feature to reduce deflectioninduced by the device (e.g., elastic, spring, etc.) coupled to theintegrally formed mounting feature. For example, the appliance caninclude a strengthened portion (e.g., via increased thickness in thearea of the mounting feature). The appliance can also be locallystiffened by embedding a reinforcing structure (e.g., a stronger andstiffer material such as stainless steel or plastic resin filler) intothe appliance to reinforce the appliance and/or mounting feature againstdeflection induced by the force from the coupled device.

The orthodontic appliances of the present disclosure can comprise any ofthe materials as disclosed herein or known to one of ordinary skill inthe art. In some embodiments, an integrally formed component may beformed from the same material as the shell of the orthodontic appliance,or a different material from the shell of the orthodontic appliance.Materials for the shell and for the integrally formed component may bechosen during design of the patient's treatment plan to facilitateachieving a goal of the patient's treatment plan. For example, the shellmay comprise a material that has a greater stiffness and/or tensilestrength compared to an integrally formed component such as a corrugatedfeature. Alternatively, the shell may comprise a material that has areduced stiffness and/or tensile strength compared to an integrallyformed component such as a hook.

Orthodontic Appliances with Power Arms

In some embodiments, the orthodontic appliances herein include one ormore power arms. As used herein, “power arm” may refer to an elongatestructure having a first portion directly or indirectly coupled to atooth or teeth, and a second portion extending along a gingivaldirection, such that force(s) and/or moment(s) applied to the secondportion (e.g., via a coupled elastic) are transmitted to the coupledtooth or teeth. In some embodiments, an orthodontic appliance includes apair of power arms connected to each other by a connecting structure(e.g., an elastic, spring, or the like). The connecting structure, whichmay also be referred to herein as a “spring structure” or an “elasticspring connector,” can apply forces and/or torques to the power armsthat are transmitted to the coupled teeth.

The power arms as disclosed herein can be directly fabricated andcoupled to the teeth in many ways. For example, power arms can bedirectly fabricated with an appliance during the direct fabricationprocess, such that the resultant appliance includes integrally formedpower arms. The power arms can be configured to couple to the teeth withthe appliance placed on the teeth. The power arms directly fabricatedwith the appliance have the advantage of altering (e.g., increasing ordecreasing) the force applied to the teeth at an intended location,relative to an appliance without power arms. The power arms can have acustom shape determined based on a three-dimensional scan data of theteeth and associated structures, such as the gums and clearance with thecheek. The directly fabricated appliance with power arms may comprise asimilar modulus material for the power arms and the appliance. Thestiffness of the appliance at various locations could be determinedbased on the thickness of the material. For example, where a locallystiffer structure is helpful, a thicker structure can be provided to addrigidity. As another example, the second moment of area of an appliancestructure can be modified in order to increase the stiffness of thestructure. Alternatively or in combination, the appliance may comprisedifferent material properties, such as a more rigid material. Therigidity of the material can be varied by varying an amount of crosslinking. The appliance and power arms may comprise different materials,such as different prepolymer and polymer materials.

The appliance with power arms can be one of a plurality of applianceswith power arms to be placed on teeth in series in accordance with anorthodontic treatment plan. The structure of the power arms and theappliance can vary in accordance with the treatment plan to providedesired forces to the teeth.

In one aspect, an appliance for placement on teeth of a patient isprovided. The appliance can comprise: a plurality of power arms; aconnecting structure coupled to the plurality of power arms to apply afirst force to the plurality of power arms; and a counter-forceconnector coupled to the plurality of power arms to apply a second forceto the plurality of power arms opposing the first force.

In some embodiments, the connecting structure comprises a rest lengthand the counter-force connector comprises a length different than therest length of the connecting structure. The length of the counter-forceconnector can be shorter than the rest length of the connectingstructure such that the connecting structure is compressed when thecounter-force connector is coupled to the plurality of power arms. Thelength of the counter-force connector can be longer than the rest lengthof the connecting structure such that the connecting structure isstretched when the counter-force connector is coupled to the pluralityof power arms.

In some embodiments, the connecting structure is an elastic springstructure.

In some embodiments, the plurality of power arms each comprise anattachment shaped for bonding to a surface of a respective tooth.

In some embodiments, the appliance further comprises a shell comprisinga plurality of tooth-receiving cavities, wherein the plurality of powerarms is coupled to the shell. The plurality of power arms can beintegrally formed with the shell by direct fabrication.

In some embodiments, the plurality of power arms is integrally formedwith one or more of the connecting structure or the counter-forceconnector by direct fabrication.

In another aspect, a method for treating a patient's teeth is provided.The method can comprise: placing the appliance of any of the embodimentsherein on the patient's teeth; and removing the counter-force connectorfrom the appliance, such that the first force applied by the connectingstructure to the plurality of power arms is transmitted to the patient'steeth.

In another aspect, a method of fabricating an orthodontic appliance isprovided. The method can comprise: determining a movement path to moveone or more teeth from an initial arrangement to a target arrangement;determining an appliance geometry for an orthodontic applianceconfigured to produce movement of the one or more teeth from the initialarrangement to the target arrangement, the orthodontic appliancecomprising a plurality of power arms; and generating instructions fordirect fabrication of the orthodontic appliance comprising the pluralityof power arms.

In some embodiments, the orthodontic appliance further comprises aconnecting structure coupled to the plurality of power arms to apply afirst force to the plurality of power arms.

In some embodiments, the orthodontic appliance further comprises acounter-force connector coupled to the plurality of power arms to applya second force to the plurality of power arms opposing the first force.The connecting structure can comprise a rest length and thecounter-force connector can comprise a length different than the restlength of the connecting structure. The length of the counter-forceconnector can be shorter than the rest length of the connectingstructure such that the connecting structure is compressed when thecounter-force connector is coupled to the plurality of power arms. Thelength of the counter-force connector can be longer than the rest lengthof the connecting structure such that the connecting structure isstretched when the counter-force connector is coupled to the pluralityof power arms.

In some embodiments, the instructions are configured to cause afabrication machine to integrally form the plurality of power arms withthe connecting structure and the counter-force connector.

In some embodiments, the plurality of power arms each comprise anattachment shaped for bonding to a surface of a respective tooth.

In some embodiments, the orthodontic appliance further comprises a shellcomprising a plurality of tooth-receiving cavities, and the plurality ofpower arms is coupled to the shell. The instructions can be configuredto cause a fabrication machine to integrally form the plurality of powerarms with the shell.

In another aspect, an appliance for placement on teeth of a patient isprovided. The appliance can comprise: a plurality of power arms; aconnecting structure extending between the power arms to apply force tothe power arms; and a counter-force connector extending between thepower arms.

In some embodiments, the counter-force connector holds the power arms ata separation distance and/or angle to each other. The power arms can beconfigured to engage a pair of teeth to torque to the teeth with anamount of force from the connecting structure. The counter-forceconnector can be configured for removal to apply the torque to the teethwith the force from the connecting structure when the power arms havebeen coupled to the teeth.

In some embodiments, the appliance further comprises a tooth locatingstructure shaped to receive at least a portion of a tooth.

In some embodiments, the plurality of power arms each comprises anattachment.

In some embodiments, the connecting structure is a preloaded springstructure comprising a predetermined amount of force.

In some embodiments, the appliance has been directly fabricated.

In some embodiments, the power arms comprise a shape profile determinedin response to three-dimensional scan data of the patient's oral cavity.

In another aspect, an appliance for placement on teeth of a patient isprovided. The appliance can comprise: a polymeric shell comprising aplurality of teeth receiving cavities; and a plurality of power armsextending from the shell to engage the teeth with force transmittedthrough the shell.

In some embodiments, the polymeric shell and the plurality of power armshave been directly fabricated together.

In some embodiments, the appliance further comprises a connectingstructure extending between the power arms to rotate one or more teeth.The connecting structure can have been directly fabricated with thepolymeric shell and the power arms. The connecting structure can beconfigured to provide a predetermined amount of force to the power armswhen placed on the teeth.

In some embodiments, the plurality of power arms comprises a shapeprofile determined in response to three-dimensional scan data of thepatient's oral cavity.

In some embodiments, the polymeric shell and the plurality of power armsare part of a treatment plan comprising a plurality of appliances, theplurality of appliances each having a plurality of power arms to moveteeth in accordance with a treatment plan.

In some embodiments, the appliance further comprises: a preloaded springstructure extending between the power arms; and a counter forceconnector extending between the power arms.

In another aspect, a method of fabricating an appliance is provided. Themethod can comprise: receiving scan profile data of a mouth of apatient; determining a shape profile of a plurality of power arms inresponse to the scan profile data of the mouth; and outputting directfabrication instructions to manufacture the appliance with the pluralityof power arms.

In some embodiments, the appliance and the plurality of power arms aredirectly fabricated.

In another aspect, a method comprising providing an appliance as in anyone of the embodiments herein.

FIG. 31 illustrates an orthodontic appliance 3100 comprising a pair ofdirectly fabricated power arms 3101, in accordance with embodiments. Thepower arms 3101 are coupled to an appliance shell 3102 at connectionpoints 3103. The appliance shell 3102 comprises a plurality oftooth-receiving cavities, each of which may fit a patient's tooth inorder to apply tooth-moving forces. In some embodiments, the connectionpoints 3103 may comprise a direct material connection formed duringfabrication of the appliance.

The power arms are connected via a connecting structure 3104 (e.g., anelastic, spring, or the like) which applies an elastic force on powerarms 3101, which in turn allows power arms 3101 to apply a tooth-movingforce on a patient's teeth. In particular, the power arms 3101 act as alever, applying force and/or torque to connection points 3103, andthereby to the appliance shell 3102. The appliance shell, in turn,applies force on a patient's teeth through contact between the teeth andthe tooth-receiving cavities of the shell. By choosing properties suchas the length and connection points of power arms, it may be possible toapply force on teeth at or near their center of resistance, withoutinducing unwanted tipping. In order to act as an effective lever, powerarms 3101 can be fabricated from a rigid material, which may differ fromthe material from which the shell 3102 or the connecting structure 3104are fabricated, for example.

An orthodontic appliance with power arms can be fabricated in a varietyof ways. In some embodiments, the power arms and connecting structurecan be directly fabricated concurrently with the appliance shell, suchthat the power arms and connecting structure are both integrally formedwith the shell. The power arms can be fabricated with or without theconnecting structure. Although the connecting structure can be optional,such that the patient places elastic bands on the teeth, in someembodiments, the connecting structure 3104 is directly fabricated withthe appliance and power arms with direct fabrication as describedherein. The directly fabricated connecting structure has the advantageof applying force to the power arms without the patient placing anelastic band on the power arm. The connecting structure, appliance, andpower arms can be directly fabricated in a free standing unloadedconfiguration such that when the aligner is placed on the teeth anddeformed, the resulting strain and deformation to the connector springstructure results in force(s) and/or moment(s) applied from theconnector to the power arms.

In alternative embodiments, the power arms can be directly fabricatedconcurrently with the appliance shell, while the connecting structure isfabricated separately. In such embodiments, the power arms areintegrally formed with the shell, while the connecting structure is aseparate component that is subsequently coupled to the power arms, e.g.,before or while the appliance is worn by the patient. The connectingstructure may or may not be produced by direct fabrication techniques.

In alternative embodiments, the power arms can be directly fabricatedconcurrently with the connecting structure, while the appliance shell isfabricated separately. In such embodiments, the power arms areintegrally formed with the connecting structure, while the applianceshell is a separate component that is subsequently coupled to the powerarms, e.g., before or while the appliance is worn by the patient. Theappliance shell may or may not be produced by direct fabricationtechniques.

In alternative embodiments, the appliance shell, power arms, andconnecting structure can each be fabricated separately and subsequentlyassembled to produce an orthodontic appliance with power arms. Theappliance shell, power arms, and/or connecting structure can be producedusing direct fabrication techniques, or can be produced using othertechniques (e.g., indirect fabrication), as desired.

Depending on the chosen design of the connecting structure 3104, anoutward force or an inward force may be provided. The direction of theforce may be determined by the rest length of the connecting structure3104 relative to the distance 3105 between connection points, wherein alonger rest length causes an outward force and a shorter rest lengthshorter causes an inward force. The magnitude may be determined by boththe spring constant of the connecting structure 3104 and the magnitudeof difference between the rest length of the connecting structure 3104and the distance 3105 between connection points, as may be approximated,for example, by Hooke's Law. In some embodiments, the connectingstructure 3104 may be replaced with a separately-applied elasticmaterial such as a band, and in some embodiments, a band may be combinedwith the connecting structure 3104 to provide increased elastic force.In some embodiments, an appliance may comprise a plurality of power armpairs, each pair connected with an elastic spring structure.

In some embodiments, the connection points 3103 may comprise an adhesiveconnection between power arms 3101 and shell 3102, for example.

In some embodiments, the connection points may comprise an interlockmechanism whereby the power arms 3101 may be removably connected toshell 3102, for example.

In some embodiments, power arms may attach to caps comprisingtooth-receiving cavities configured to receive teeth. In someembodiments, power arms may be bonded directly to teeth without need forattachments. In some embodiments, an orthodontic appliance may beconfigured to be placed onto teeth to which power arms are bonded, forexample comprising spaces through which power arms may extend. In someembodiments, an orthodontic appliance may be configured to fit over capscomprising power arms.

In some embodiments, power arms may apply force to adjacent teeth, andin some embodiments, power arms may apply force to non-adjacent teeth.

FIG. 32 illustrates a patient's mouth, in which a directly fabricatedpower arm 3201 comprising attachment 3203 is coupled to a tooth 3202 toapply a tooth-moving force, in accordance with embodiments. The couplingis accomplished with attachment 3203 comprising power arm 3201 bonded tothe tooth 3202. The bonding of the attachment to the tooth may comprisean adhesive connecting the attachment to the tooth. The power arm iscoupled to another power arm as described herein by a connectingstructure 3204, to provide a tooth-moving force on the tooth 3202 asdescribed herein. The three-dimensional shape of the power arm can bedetermined in response to a scan of the patient's oral cavity asdescribed herein. A similar directly fabricated attachment and power armcan be provided on another tooth and coupled to power arm 3201,attachment 3203 and connecting structure 3203 as described herein, andeach of these components can be directly fabricated together to provideimproved attachment with power arms on the teeth. The power arm 3201 maybe bonded to the attachment 3203, the two may be directly fabricated asa single object, or the two may connect using an interlock mechanism.

FIGS. 33A through 33C illustrate various spring structures that may bedirectly fabricated as part of a power arm structure, in accordance withembodiments. The structures illustrated may be readily manufactured bythe direct fabrication methods disclosed herein, and may beinterchangeably used in any of the appliance and power arm structuresdisclosed herein. In power arm structure 3300, power arms 3301 areconnected by an accordion-shaped elastic spring structure 3302, whichprovides an elastic force on power arms 3301, as determined by itsspring constant and rest length. In power arm structure 3310, power arms3311 are connected by a helical-coil elastic spring structure 3312,which provides an elastic force on power arms 3311, as determined by itsspring constant and rest length. In power arm structure 3320, power arms3321 are connected by a spring structure 3322 comprising an elasticmaterial, which provides an elastic force on power arms 3321, asdetermined by its spring constant and rest length. The elastic materialmay be chosen on the basis of the spring constant desired, as determinedby its elasticity. In some cases, the elastic material may comprise arelatively rigid material that expands when in contact with a patient'ssaliva; for example, a hydrophilic polymer. As the polymer swells, itpushes the power arms apart, allowing them to provide a tooth movingforce. The use of such swelling materials may allow the fabrication ofpower arms that only apply force on their attachment points whenactually worn by the patient. In some embodiments, the material mayinclude shape memory material that has a first shape outside the mouth,for example, at room temperature, and has a shape inside the mouth, forexample, at body temperature. Shape memory material may change shapebased on temperature, for example, by contracting or expanding.

The directly fabricated attachments and power arms can be preloaded in aspaced apart configuration to provide a desired amount of torque to thepatient's teeth. When placing preloaded power arms and an attachmentinto the mouth of a patient, it may be desirable to avoid applying forceuntil the installation of the power arms is complete to facilitatehandling and placement. For example, a preloading structure can beprovided such that the person placing the directly fabricated power armswith the attachment does not have to urge the two attachments togetherto load the spring when the attachments are placed on the teeth, therebyfacilitating placement.

FIG. 34 illustrates a pre-loaded assembly 3400 of directly fabricatedcomponents comprising power arms 3401 having attachments 3406, apreloaded spring structure 3402, optionally a counter-force connector3404, and a locating structure 3403, in accordance with embodiments. Thecounter-force connector 3404 balances the power arm's tooth-moving forcewith an opposing force for easier placement on a patient's teeth. Thelocating structures 3403 are configured to receive structures of thepatient's teeth in order to place the attachments at a predeterminedlocation on the teeth. The locating structures 3403 may comprise aplurality of tooth receiving cavities, or engagement structures tocouple to a portion of a received tooth such as an occlusal surface oran interproximal surface, for example.

As the power arms are placed with the locating structure 3403, they willtypically place connecting structure 3402 under strain, which may makeplacement difficult. To compensate for this problem, a counter-forceconnecter 3404 may be included to balance out the force of connectingstructure 3402. Counter-force connector 3404 may be connected tolocating structure 3403, and may be fabricated as a part of power arms3401. Counter-force connector 3404 may be fabricated from a rigidmaterial, and configured to relieve the strain from connecting structure3402 by pulling or pushing in the opposite direction as needed. In thecase where counter-force connecter 3404 is fabricated as part of powerarms 3401, counter-force connecter 3404 may be cut by the orthodontistafter installation of power arms is finished, in order to allowconnecting structure 3402 to apply an unimpeded force on the patient'steeth. In some cases, it may be desirable to smooth the surfaces ofpower arms 3401 after cutting counter-force connecter 3404, so as toavoid uncomfortable surfaces or sharp edges within the patient's mouth.

The pre-loading structure 3400 comprises a pair of power arms connectedby a connecting structure 3402. The power arms are disposed within alocating structure 3403, which may comprise at least a portion anappliance worn by the patient, for example. The locating structure 3403can be directly fabricated with the power arms and attachments, and canbe sized and shaped for placement on the patient's teeth in order toposition the attachments at desired locations 3405 on the teeth. Thelocating structure 3403 can be removed subsequent to placement andbonding of the attachments to the patient's teeth.

FIGS. 35A through 35C illustrate the operation of the counter-forceconnecter to pre-load a pair of power arms for installation, inaccordance with embodiments. The power arms may be initially fabricatedin a relaxed state 3500, comprising a plurality of power arms 3501,connected by a connecting structure 3502 that is uncompressed. A firstpower arm of the plurality of the power arms 3501 further comprises acounter-force connector 3504, connected to the first power arm. Thecounter-force connector 3504 comprises a mechanism, such as hook 3505,that lets it attach to a second power arm of the plurality of powerarms. Because the length of the counter-force connector 3504 is shorterthan the rest length of the connecting structure 3502, the connectingstructure 3502 is compressed when counter-force connector 3504 isconnected to the second power arm, as shown in pre-loaded state 3510.After then installing the power arms into a dental appliance orattaching them to the tooth, the counter-force connector may be removed,for example by cutting or breaking it at junction 3503 and/or unhookinghook 3505, allowing the power arms to apply outwardly-directed force(s)to the teeth of a patient (e.g., to increase a space between teeth), asillustrated in installed state 3520. In some cases, counter-forceconnector may comprise hooks or other attachment mechanisms at each end,so that it may be more easily removed after use.

FIGS. 36A through 36C illustrate the operation of the counter-forceconnecter to pre-load a pair of power arms for installation, inaccordance with embodiments. The power arms may be initially fabricatedin a relaxed state 3600, comprising a plurality of power arms 3601,connected by a connecting structure 3602 that is uncompressed. A firstpower arm of the plurality of the power arms 3601 further comprises acounter-force connector 3604, connected to the first power arm. Thecounter-force connector 3604 comprises a mechanism, such as hook 3605,that lets it attach to a second power arm of the plurality of powerarms. Because the length of counter-force connector 3604 is longer thanthe rest length of the connecting structure 3602, the connectingstructure 3602 is stretched when counter-force connector 3604 isconnected to the second power arm, as shown in pre-loaded state 3610.After then installing the power arms into a dental appliance orattaching them to the tooth, the counter-force connector may be removed,for example by cutting or breaking it at junction 3603 and/or unhookinghook 3605, allowing the power arms to apply inward-directed force(s) tothe teeth of a patient (e.g., for space closure), as illustrated ininstalled state 3620. In some cases, counter-force connector maycomprise hooks or other attachment mechanisms at each end, so that itmay be more easily removed after use.

FIGS. 37A through 37D illustrate embodiments of single power armappliances. In some embodiments, a single power arm can be used to moveteeth. Force on the power arm can be reacted against an aligner, againsta button mounted on a tooth, or against a TAD or other structure. FIG.37A shows a single power arm appliance 3700 including a single power arm3701 and an aligner 3703. A first end 3709 of the power arm 3701 isattached to the aligner 3703. In some embodiments, the first end 3709 isbonded directly to a tooth. A second end of the power arm 3701 isconnected to a connecting structure 3702, which may also be an elasticelement. The terminal end of the connecting structure 3702 includes acoupling 3708, such as a hook, that engages with a correspondingcoupling 3706, such as a hook, loop, or other coupling, that isintegrated with the aligner 3703. Force is transmitted between the powerarm 3701 and the aligner hook 3706 via the connecting structure 3702 tomove a patient's teeth.

FIG. 37B shows a single power arm appliance 3720 including a singlepower arm 3721. A first end 3729 of the power arm 3721 is attacheddirectly to one of a patient's teeth while a second end of the power arm3721 is connected to a connecting structure 3722. The terminal end ofthe connecting structure 3722 includes a coupling 3728, for example aneye hook, that engages with a corresponding coupling 3726, such as a TADthat is implanted in the patient. Force is transmitted between the powerarm 3721 and the TAD via the connecting structure 3722 to move apatient's teeth.

FIG. 37C shows a single power arm appliance 3740 including a singlepower arm 3741. A first end 3749 of the power arm 3741 is attacheddirectly to one of a patient's teeth while a second end of the power arm3741 is connected to a connecting structure 3742. The terminal end ofthe connecting structure 3742 includes a hook 3748 that engages with acorresponding button 3746 that is attached to one of the patient'steeth. Force is transmitted between the power arm 3741 and the button3746 via the connecting structure 3742 to move a patient's teeth.

FIG. 37D shows a single power arm appliance 3760 including a singlepower arm 3761 and an aligner 3763. A first end 3769 of the power arm3761 is attached to or integrated with the aligner 3763 at a firstlocation on the aligner while a second end of the power arm 3761 isconnected to a connecting structure 3762. The terminal end 3768 of theconnecting structure 3762 is also attached to or integrated with thealigner 3703 at a second location on the aligner. Force is transmittedbetween the power arm 3761 and the second location on the aligner viathe connecting structure 3762 to move a patient's teeth.

In some embodiments, a single power arm can have a first end bonded to afirst tooth and a second end bonded, via a connecting structure, to asecond tooth.

Direct Fabrication of Orthodontic Appliances

The various embodiments of the orthodontic appliances presented hereincan be fabricated in a wide variety of ways. In some embodiments, theorthodontic appliances herein (or portions thereof) can be producedusing direct fabrication, such as additive manufacturing techniques(also referred to herein as “3D printing) or subtractive manufacturingtechniques (e.g., milling). In some embodiments, direct fabricationinvolves forming an object (e.g., an orthodontic appliance or a portionthereof) without using a physical template (e.g., mold, mask etc.) todefine the object geometry. Additive manufacturing techniques can becategorized as follows: (1) vat photopolymerization (e.g.,stereolithography), in which an object is constructed layer by layerfrom a vat of liquid photopolymer resin; (2) material jetting, in whichmaterial is jetted onto a build platform using either a continuous ordrop on demand (DOD) approach; (3) binder jetting, in which alternatinglayers of a build material (e.g., a powder-based material) and a bindingmaterial (e.g., a liquid binder) are deposited by a print head; (4)fused deposition modeling (FDM), in which material is drawn though anozzle, heated, and deposited layer by layer; (5) powder bed fusion,including but not limited to direct metal laser sintering (DMLS),electron beam melting (EBM), selective heat sintering (SHS), selectivelaser melting (SLM), and selective laser sintering (SLS); (6) sheetlamination, including but not limited to laminated object manufacturing(LOM) and ultrasonic additive manufacturing (UAM); and (7) directedenergy deposition, including but not limited to laser engineering netshaping, directed light fabrication, direct metal deposition, and 3Dlaser cladding. For example, stereolithography can be used to directlyfabricate one or more of the appliances herein. In some embodiments,stereolithography involves selective polymerization of a photosensitiveresin (e.g., a photopolymer) according to a desired cross-sectionalshape using light (e.g., ultraviolet light). The object geometry can bebuilt up in a layer-by-layer fashion by sequentially polymerizing aplurality of object cross-sections. As another example, the appliancesherein can be directly fabricated using selective laser sintering. Insome embodiments, selective laser sintering involves using a laser beamto selectively melt and fuse a layer of powdered material according to adesired cross-sectional shape in order to build up the object geometry.As yet another example, the appliances herein can be directly fabricatedby fused deposition modeling. In some embodiments, fused depositionmodeling involves melting and selectively depositing a thin filament ofthermoplastic polymer in a layer-by-layer manner in order to form anobject. In yet another example, material jetting can be used to directlyfabricate the appliances herein. In some embodiments, material jettinginvolves jetting or extruding one or more materials onto a build surfacein order to form successive layers of the object geometry.

In some embodiments, the direct fabrication methods provided hereinbuild up the object geometry in a layer-by-layer fashion, withsuccessive layers being formed in discrete build steps. Alternatively orin combination, direct fabrication methods that allow for continuousbuild-up of an object geometry can be used, referred to herein as“continuous direct fabrication.” Various types of continuous directfabrication methods can be used. As an example, in some embodiments, theappliances herein are fabricated using “continuous liquid interphaseprinting,” in which an object is continuously built up from a reservoirof photopolymerizable resin by forming a gradient of partially curedresin between the building surface of the object and apolymerization-inhibited “dead zone.” In some embodiments, asemi-permeable membrane is used to control transport of aphotopolymerization inhibitor (e.g., oxygen) into the dead zone in orderto form the polymerization gradient. Continuous liquid interphaseprinting can achieve fabrication speeds about 25 times to about 100times faster than other direct fabrication methods, and speeds about1000 times faster can be achieved with the incorporation of coolingsystems. Continuous liquid interphase printing is described in U.S.Patent Publication Nos. 2015/0097315, 2015/0097316, and 2015/0102532,the disclosures of each of which are incorporated herein by reference intheir entirety.

As another example, a continuous direct fabrication method can achievecontinuous build-up of an object geometry by continuous movement of thebuild platform (e.g., along the vertical or Z-direction) during theirradiation phase, such that the hardening depth of the irradiatedphotopolymer is controlled by the movement speed. Accordingly,continuous polymerization of material on the build surface can beachieved. Such methods are described in U.S. Pat. No. 7,892,474, thedisclosure of which is incorporated herein by reference in its entirety.

In another example, a continuous direct fabrication method can involveextruding a composite material composed of a curable liquid materialsurrounding a solid strand. The composite material can be extruded alonga continuous three-dimensional path in order to form the object. Suchmethods are described in U.S. Patent Publication No. 2014/0061974, thedisclosure of which is incorporated herein by reference in its entirety.

In yet another example, a continuous direct fabrication method utilizesa “heliolithography” approach in which the liquid photopolymer is curedwith focused radiation while the build platform is continuously rotatedand raised. Accordingly, the object geometry can be continuously builtup along a spiral build path. Such methods are described in U.S. PatentPublication No. 2014/0265034, the disclosure of which is incorporatedherein by reference in its entirety.

The direct fabrication approaches provided herein are compatible with awide variety of materials, including but not limited to one or more ofthe following: polymer matrix reinforced with ceramic or metallicpolymers, a polyester, a co-polyester, a polycarbonate, a thermoplasticpolyurethane, a polypropylene, a polyethylene, a polypropylene andpolyethylene copolymer, an acrylic, a cyclic block copolymer, apolyetheretherketone, a polyamide, a polyethylene terephthalate, apolybutylene terephthalate, a polyetherimide, a polyethersulfone, apolytrimethylene terephthalate, a styrenic block copolymer (SBC), asilicone rubber, an elastomeric alloy, a thermoplastic elastomer (TPE),a thermoplastic vulcanizate (TPV) elastomer, a polyurethane elastomer, ablock copolymer elastomer, a polyolefin blend elastomer, a thermoplasticco-polyester elastomer, a thermoplastic polyamide elastomer, orcombinations thereof. The materials used for direct fabrication can beprovided in an uncured form (e.g., as a liquid, resin, powder, etc.) andcan be cured (e.g., by photopolymerization, light curing, gas curing,laser curing, crosslinking, etc.) in order to form an orthodonticappliance or a portion thereof. The properties of the material beforecuring may differ from the properties of the material after curing. Oncecured, the materials herein can exhibit sufficient strength, stiffness,durability, biocompatibility, etc. for use in an orthodontic appliance.The post-curing properties of the materials used can be selectedaccording to the desired properties for the corresponding portions ofthe appliance.

In some embodiments, relatively rigid portions of the orthodonticappliance can be formed via direct fabrication using one or more of thefollowing materials: a polyester, a co-polyester, a polycarbonate, athermoplastic polyurethane, a polypropylene, a polyethylene, apolypropylene and polyethylene copolymer, an acrylic, a cyclic blockcopolymer, a polyetheretherketone, a polyamide, a polyethyleneterephthalate, a polybutylene terephthalate, a polyetherimide, apolyethersulfone, and/or a polytrimethylene terephthalate.

In some embodiments, relatively elastic portions of the orthodonticappliance can be formed via direct fabrication using one or more of thefollowing materials: a styrenic block copolymer (SBC), a siliconerubber, an elastomeric alloy, a thermoplastic elastomer (TPE), athermoplastic vulcanizate (TPV) elastomer, a polyurethane elastomer, ablock copolymer elastomer, a polyolefin blend elastomer, a thermoplasticco-polyester elastomer, and/or a thermoplastic polyamide elastomer.

Optionally, the direct fabrication methods described herein allow forfabrication of an appliance including multiple materials, referred toherein as “multi-material direct fabrication.” In some embodiments, amulti-material direct fabrication method involves concurrently formingan object from multiple materials in a single manufacturing step usingthe same fabrication machine and method. For instance, a multi-tipextrusion apparatus can be used to selectively dispense multiple typesof materials (e.g., resins, liquids, solids, or combinations thereof)from distinct material supply sources in order to fabricate an objectfrom a plurality of different materials. Such methods are described inU.S. Pat. No. 6,749,414, the disclosure of which is incorporated hereinby reference in its entirety. Alternatively or in combination, amulti-material direct fabrication method can involve forming an objectfrom multiple materials in a plurality of sequential manufacturingsteps. For instance, a first portion of the object can be formed from afirst material in accordance with any of the direct fabrication methodsherein, then a second portion of the object can be formed from a secondmaterial in accordance with methods herein, and so on, until theentirety of the object has been formed. The relative arrangement of thefirst and second portions can be varied as desired, e.g., the firstportion can be partially or wholly encapsulated by the second portion ofthe object. The sequential manufacturing steps can be performed usingthe same fabrication machine or different fabrication machines, and canbe performed using the same fabrication method or different fabricationmethods. For example, a sequential multi-manufacturing procedure caninvolve forming a first portion of the object using stereolithographyand a second portion of the object using fused deposition modeling.

Direct fabrication can provide various advantages compared to othermanufacturing approaches. For instance, in contrast to indirectfabrication, direct fabrication permits production of an orthodonticappliance without utilizing any molds or templates for shaping theappliance, thus reducing the number of manufacturing steps involved andimproving the resolution and accuracy of the final appliance geometry.Additionally, direct fabrication permits precise control over thethree-dimensional geometry of the appliance, such as the appliancethickness. Complex structures and/or auxiliary components can be formedintegrally as a single piece with the appliance shell in a singlemanufacturing step, rather than being added to the shell in a separatemanufacturing step. In some embodiments, direct fabrication is used toproduce appliance geometries that would be difficult to create usingalternative manufacturing techniques, such as appliances with very smallor fine features, complex geometric shapes, undercuts, interproximalstructures, shells with variable thicknesses, and/or internal structures(e.g., for improving strength with reduced weight and material usage).For example, in some embodiments, the direct fabrication approachesherein permit fabrication of an orthodontic appliance with feature sizesof less than or equal to about 5 μm, or within a range from about 5 μmto about 50 μm, or within a range from about 20 μm to about 50 μm.

The direct fabrication techniques described herein can be used toproduce appliances with substantially isotropic material properties,e.g., substantially the same or similar strengths along all directions.In some embodiments, the direct fabrication approaches herein permitproduction of an orthodontic appliance with a strength that varies by nomore than about 25%, about 20%, about 15%, about 10%, about 5%, about1%, or about 0.5% along all directions. Additionally, the directfabrication approaches herein can be used to produce orthodonticappliances at a faster speed compared to other manufacturing techniques.In some embodiments, the direct fabrication approaches herein allow forproduction of an orthodontic appliance in a time interval less than orequal to about 1 hour, about 30 minutes, about 25 minutes, about 20minutes, about 15 minutes, about 10 minutes, about 5 minutes, about 4minutes, about 3 minutes, about 2 minutes, about 1 minutes, or about 30seconds. Such manufacturing speeds allow for rapid “chair-side”production of customized appliances, e.g., during a routine appointmentor checkup.

In some embodiments, the direct fabrication methods described hereinimplement process controls for various machine parameters of a directfabrication system or device in order to ensure that the resultantappliances are fabricated with a high degree of precision. Suchprecision can be beneficial for ensuring accurate delivery of a desiredforce system to the teeth in order to effectively elicit toothmovements. Process controls can be implemented to account for processvariability arising from multiple sources, such as the materialproperties, machine parameters, environmental variables, and/orpost-processing parameters.

Material properties may vary depending on the properties of rawmaterials, purity of raw materials, and/or process variables duringmixing of the raw materials. In many embodiments, resins or othermaterials for direct fabrication should be manufactured with tightprocess control to ensure little variability in photo-characteristics,material properties (e.g., viscosity, surface tension), physicalproperties (e.g., modulus, strength, elongation) and/or thermalproperties (e.g., glass transition temperature, heat deflectiontemperature). Process control for a material manufacturing process canbe achieved with screening of raw materials for physical propertiesand/or control of temperature, humidity, and/or other process parametersduring the mixing process. By implementing process controls for thematerial manufacturing procedure, reduced variability of processparameters and more uniform material properties for each batch ofmaterial can be achieved. Residual variability in material propertiescan be compensated with process control on the machine, as discussedfurther herein.

Machine parameters can include curing parameters. For digital lightprocessing (DLP)-based curing systems, curing parameters can includepower, curing time, and/or grayscale of the full image. For laser-basedcuring systems, curing parameters can include power, speed, beam size,beam shape and/or power distribution of the beam. For printing systems,curing parameters can include material drop size, viscosity, and/orcuring power. These machine parameters can be monitored and adjusted ona regular basis (e.g., some parameters at every 1-x layers and someparameters after each build) as part of the process control on thefabrication machine. Process control can be achieved by including asensor on the machine that measures power and other beam parametersevery layer or every few seconds and automatically adjusts them with afeedback loop. For DLP machines, gray scale can be measured andcalibrated before, during, and/or at the end of each build, and/or atpredetermined time intervals (e.g., every n^(th) build, once per hour,once per day, once per week, etc.), depending on the stability of thesystem. In addition, material properties and/or photo-characteristicscan be provided to the fabrication machine, and a machine processcontrol module can use these parameters to adjust machine parameters(e.g., power, time, gray scale, etc.) to compensate for variability inmaterial properties. By implementing process controls for thefabrication machine, reduced variability in appliance accuracy andresidual stress can be achieved.

In many embodiments, environmental variables (e.g., temperature,humidity, Sunlight or exposure to other energy/curing source) aremaintained in a tight range to reduce variable in appliance thicknessand/or other properties. Optionally, machine parameters can be adjustedto compensate for environmental variables.

In many embodiments, post-processing of appliances includes cleaning,post-curing, and/or support removal processes. Relevant post-processingparameters can include purity of cleaning agent, cleaning pressureand/or temperature, cleaning time, post-curing energy and/or time,and/or consistency of support removal process. These parameters can bemeasured and adjusted as part of a process control scheme. In addition,appliance physical properties can be varied by modifying thepost-processing parameters. Adjusting post-processing machine parameterscan provide another way to compensate for variability in materialproperties and/or machine properties.

Although various embodiments herein are described with respect to directfabrication techniques, it shall be appreciated that other techniquescan also be used, such as indirect fabrication techniques. In someembodiments, the appliances herein (or portions thereof) can be producedusing indirect fabrication techniques, such as by thermoforming over apositive or negative mold. Indirect fabrication of an orthodonticappliance can involve one or more of the following steps: producing apositive or negative mold of the patient's dentition in a targetarrangement (e.g., by additive manufacturing, milling, etc.),thermoforming one or more sheets of material over the mold in order togenerate an appliance shell, forming one or more structures in the shell(e.g., by cutting, etching, etc.), and/or coupling one or morecomponents to the shell (e.g., by extrusion, additive manufacturing,spraying, thermoforming, adhesives, bonding, fasteners, etc.).Optionally, one or more auxiliary appliance components as describedherein (e.g., elastics, wires, springs, bars, arch expanders, palatalexpanders, twin blocks, occlusal blocks, bite ramps, mandibularadvancement splints, bite plates, pontics, hooks, brackets, headgeartubes, bumper tubes, palatal bars, frameworks, pin-and-tube apparatuses,buccal shields, buccinator bows, wire shields, lingual flanges and pads,lip pads or bumpers, protrusions, divots, etc.) are formed separatelyfrom and coupled to the appliance shell (e.g., via adhesives, bonding,fasteners, mounting features, etc.) after the shell has been fabricated.

In some embodiments, the orthodontic appliances herein can be fabricatedusing a combination of direct and indirect fabrication techniques, suchthat different portions of an appliance can be fabricated usingdifferent fabrication techniques and assembled in order to form thefinal appliance. For example, an appliance shell can be formed byindirect fabrication (e.g., thermoforming), and one or more structuresor components as described herein (e.g., auxiliary components, powerarms, etc.) can be added to the shell by direct fabrication (e.g.,printing onto the shell).

Digital Design of Orthodontic Appliances

The configuration of the orthodontic appliances herein can be determinedaccording to a treatment plan for a patient, e.g., a treatment planinvolving successive administration of a plurality of appliances forincrementally repositioning teeth. Computer-based treatment planningand/or appliance manufacturing methods can be used in order tofacilitate the design and fabrication of appliances. For instance, oneor more of the appliance components described herein can be digitallydesigned and fabricated with the aid of computer-controlledmanufacturing devices (e.g., computer numerical control (CNC) milling,computer-controlled additive manufacturing such as 3D printing, etc.).The computer-based methods presented herein can improve the accuracy,flexibility, and convenience of appliance fabrication.

In some embodiments, computer-based 3-dimensional planning/design tools,such as Treat™ software from Align Technology, Inc., may be used todesign and fabricate the orthodontic appliances described herein.

FIG. 38 illustrates a method 3800 for designing an orthodontic applianceto be produced by direct fabrication, in accordance with embodiments.The method 3800 can be applied to any embodiment of the orthodonticappliances described herein. Some or all of the steps of the method 3800can be performed by any suitable data processing system or device, e.g.,one or more processors configured with suitable instructions.

In step 3810, a movement path to move one or more teeth from an initialarrangement to a target arrangement is determined. The initialarrangement can be determined from a mold or a scan of the patient'steeth or mouth tissue, e.g., using wax bites, direct contact scanning,x-ray imaging, tomographic imaging, sonographic imaging, and othertechniques for obtaining information about the position and structure ofthe teeth, jaws, gums and other orthodontically relevant tissue. Fromthe obtained data, a digital data set can be derived that represents theinitial (e.g., pretreatment) arrangement of the patient's teeth andother tissues. Optionally, the initial digital data set is processed tosegment the tissue constituents from each other. For example, datastructures that digitally represent individual tooth crowns can beproduced. Advantageously, digital models of entire teeth can beproduced, including measured or extrapolated hidden surfaces and rootstructures, as well as surrounding bone and soft tissue.

The target arrangement of the teeth (e.g., a desired and intended endresult of orthodontic treatment) can be received from a clinician in theform of a prescription, can be calculated from basic orthodonticprinciples, and/or can be extrapolated computationally from a clinicalprescription. With a specification of the desired final positions of theteeth and a digital representation of the teeth themselves, the finalposition and surface geometry of each tooth can be specified to form acomplete model of the tooth arrangement at the desired end of treatment.

Having both an initial position and a target position for each tooth, amovement path can be defined for the motion of each tooth. In someembodiments, the movement paths are configured to move the teeth in thequickest fashion with the least amount of round-tripping to bring theteeth from their initial positions to their desired target positions.The tooth paths can optionally be segmented, and the segments can becalculated so that each tooth's motion within a segment stays withinthreshold limits of linear and rotational translation. In this way, theend points of each path segment can constitute a clinically viablerepositioning, and the aggregate of segment end points can constitute aclinically viable sequence of tooth positions, so that moving from onepoint to the next in the sequence does not result in a collision ofteeth.

In step 3820, a force system to produce movement of the one or moreteeth along the movement path is determined. A force system can includeone or more forces and/or one or more torques. Different force systemscan result in different types of tooth movement, such as tipping,translation, rotation, extrusion, intrusion, root movement, etc.Biomechanical principles, modeling techniques, forcecalculation/measurement techniques, and the like, including knowledgeand approaches commonly used in orthodontia, may be used to determinethe appropriate force system to be applied to the tooth to accomplishthe tooth movement. In determining the force system to be applied,sources may be considered including literature, force systems determinedby experimentation or virtual modeling, computer-based modeling,clinical experience, minimization of unwanted forces, etc.

Determination of the force system can be performed in a variety of ways.For example, in some embodiments, the force system is determined on apatient-by-patient basis, e.g., using patient-specific data.Alternatively or in combination, the force system can be determinedbased on a generalized model of tooth movement (e.g., based onexperimentation, modeling, clinical data, etc.), such thatpatient-specific data is not necessarily used. In some embodiments,determination of a force system involves calculating specific forcevalues to be applied to one or more teeth to produce a particularmovement. Alternatively, determination of a force system can beperformed at a high level without calculating specific force values forthe teeth. For instance, step 3820 can involve determining a particulartype of force to be applied (e.g., extrusive force, intrusive force,translational force, rotational force, tipping force, torqueing force,etc.) without calculating the specific magnitude and/or direction of theforce.

In step 3830, an appliance geometry and/or material composition for anorthodontic appliance configured to produce the force system isdetermined. The appliance can be any embodiment of the appliancesdiscussed herein, such as an appliance having variable localizedproperties, integrally formed components, and/or power arms.

For example, in some embodiments, the appliance comprises aheterogeneous thickness, a heterogeneous stiffness, or a heterogeneousmaterial composition. In some embodiments, the appliance comprises twoor more of a heterogeneous thickness, a heterogeneous stiffness, or aheterogeneous material composition. In some embodiments, the appliancecomprises a heterogeneous thickness, a heterogeneous stiffness, and aheterogeneous material composition. The heterogeneous thickness,stiffness, and/or material composition can be configured to produce theforce system for moving the teeth, e.g., by preferentially applyingforces at certain locations on the teeth. For example, an appliance withheterogeneous thickness can include thicker portions that apply moreforce on the teeth than thinner portions. As another example, anappliance with heterogeneous stiffness can include stiffer portions thatapply more force on the teeth than more elastic portions. Variations instiffness can be achieved by varying the appliance thickness, materialcomposition, and/or degree of photopolymerization, as described herein.

In some embodiments, determining the appliance geometry and/or materialcomposition comprises determining the geometry and/or materialcomposition of one or more integrally formed components to be directlyfabricated with an appliance shell. The integrally formed component canbe any of the embodiments described herein. The geometry and/or materialcomposition of the integrally formed component(s) can be selected tofacilitate application of the force system onto the patient's teeth. Thematerial composition of the integrally formed component can be the sameas or different from the material composition of the shell.

In some embodiments, determining the appliance geometry and/or materialcomposition comprises determining the geometry and/or materialcomposition for a power arm design for the orthodontic appliance. Thepower arm design can utilize any of the power arm embodiments describedherein. The power arm design can be configured to produce the forcesystem is determined. Determination of the power arm design, appliancegeometry, material composition, and/or properties can be performed usinga treatment or force application simulation environment.

The step 3830 can involve analyzing the desired force system in order todetermine an appliance geometry and material composition that wouldproduce the force system. In some embodiments, the analysis involvesdetermining appliance properties (e.g., stiffness) at one or morelocations that would produce a desired force at the one or morelocations. The analysis can then involve determining an appliancegeometry and material composition at the one or more locations toachieve the specified properties. Determination of the appliancegeometry and material composition can be performed using a treatment orforce application simulation environment. A simulation environment caninclude, e.g., computer modeling systems, biomechanical systems orapparatus, and the like. Optionally, digital models of the applianceand/or teeth can be produced, such as finite element models. The finiteelement models can be created using computer program applicationsoftware available from a variety of vendors. For creating solidgeometry models, computer aided engineering (CAE) or computer aideddesign (CAD) programs can be used, such as the AutoCAD® softwareproducts available from Autodesk, Inc., of San Rafael, Calif. Forcreating finite element models and analyzing them, program products froma number of vendors can be used, including finite element analysispackages from ANSYS, Inc., of Canonsburg, Pa., and SIMULIA(Abaqus)software products from Dassault Systemes of Waltham, Mass.

Optionally, one or more appliance geometries and material compositionscan be selected for testing or force modeling. As noted above, a desiredtooth movement, as well as a force system required or desired foreliciting the desired tooth movement, can be identified. Using thesimulation environment, a candidate appliance geometry and compositioncan be analyzed or modeled for determination of an actual force systemresulting from use of the candidate appliance. One or more modificationscan optionally be made to a candidate appliance, and force modeling canbe further analyzed as described, e.g., in order to iterativelydetermine an appliance design that produces the desired force system.

Optionally, step 3830 can further involve determining the geometry ofone or more auxiliary components to be used in combination with theorthodontic appliance in order to exert the force system on the one ormore teeth. Such auxiliaries can include one or more of tooth-mountedattachments, elastics, wires, springs, bite blocks, arch expanders,wire-and-bracket appliances, shell appliances, headgear, or any otherorthodontic device or system that can be used in conjunction with theorthodontic appliances herein. The use of such auxiliary components maybe advantageous in situations where it is difficult for the appliancealone to produce the force system. Additionally, auxiliary componentscan be added to the orthodontic appliance in order to provide otherdesired functionalities besides producing the force system, such asmandibular advancement splints to treat sleep apnea, pontics to improveaesthetic appearance, and so on. In some embodiments, the auxiliarycomponents are fabricated and provided separately from the orthodonticappliance. Alternatively, the geometry of the orthodontic appliance canbe modified to include one or more auxiliary components as integrallyformed components (see, e.g., FIGS. 16-36 ).

In step 3840, instructions for fabrication of the orthodontic appliancehaving the appliance geometry and material composition are generated.The instructions can be configured to control a fabrication system ordevice in order to produce the orthodontic appliance with the specifiedappliance geometry and material composition. In some embodiments, theinstructions are configured for manufacturing the orthodontic applianceusing direct fabrication (e.g., stereolithography, selective lasersintering, fused deposition modeling, 3D printing, continuous directfabrication, multi-material direct fabrication, etc.), in accordancewith the various methods presented herein. Optionally, the instructionscan be configured to cause a fabrication machine to directly fabricatethe orthodontic appliance with variable properties, integrally formedcomponents and/or power arms, as discussed above and herein. Inalternative embodiments, the instructions can be configured for indirectfabrication of the appliance, e.g., by thermoforming.

Although the above steps show a method 3800 of designing an orthodonticappliance in accordance with some embodiments, a person of ordinaryskill in the art will recognize some variations based on the teachingdescribed herein. Some of the steps may comprise sub-steps. Some of thesteps may be repeated as often as desired. One or more steps of themethod 200 may be performed with any suitable fabrication system ordevice, such as the embodiments described herein. Some of the steps maybe optional, and the order of the steps can be varied as desired. Forinstance, in some embodiments, step 3820 is optional, such that step3830 involves determining the appliance geometry and/or materialcomposition based directly on the tooth movement path rather than basedon the force system.

FIG. 39 illustrates a method 3900 for digitally planning an orthodontictreatment and/or design or fabrication of an appliance, in accordancewith embodiments. The method 3900 can be applied to any of the treatmentprocedures described herein and can be performed by any suitable dataprocessing system.

In step 3910, a digital representation of a patient's teeth is received.The digital representation can include surface topography data for thepatient's intraoral cavity (including teeth, gingival tissues, etc.).The surface topography data can be generated by directly scanning theintraoral cavity, a physical model (positive or negative) of theintraoral cavity, or an impression of the intraoral cavity, using asuitable scanning device (e.g., a handheld scanner, desktop scanner,etc.).

In step 3920, one or more treatment stages are generated based on thedigital representation of the teeth. The treatment stages can beincremental repositioning stages of an orthodontic treatment proceduredesigned to move one or more of the patient's teeth from an initialtooth arrangement to a target arrangement. For example, the treatmentstages can be generated by determining the initial tooth arrangementindicated by the digital representation, determining a target tootharrangement, and determining movement paths of one or more teeth in theinitial arrangement necessary to achieve the target tooth arrangement.The movement path can be optimized based on minimizing the totaldistance moved, preventing collisions between teeth, avoiding toothmovements that are more difficult to achieve, or any other suitablecriteria.

In step 3930, at least one orthodontic appliance is fabricated based onthe generated treatment stages. For example, a set of appliances can befabricated, each shaped according a tooth arrangement specified by oneof the treatment stages, such that the appliances can be sequentiallyworn by the patient to incrementally reposition the teeth from theinitial arrangement to the target arrangement. The appliance set mayinclude one or more of the orthodontic appliances described herein. Thefabrication of the appliance may involve creating a digital model of theappliance to be used as input to a computer-controlled fabricationsystem. The appliance can be formed using direct fabrication methods,indirect fabrication methods, or combinations thereof, as desired.

In some instances, staging of various arrangements or treatment stagesmay not be necessary for design and/or fabrication of an appliance. Asillustrated by the dashed line in FIG. 39 , design and/or fabrication ofan orthodontic appliance, and perhaps a particular orthodontictreatment, may include use of a representation of the patient's teeth(e.g., receive a digital representation of the patient's teeth 3910),followed by design and/or fabrication of an orthodontic appliance basedon a representation of the patient's teeth in the arrangementrepresented by the received representation.

Optionally, some or all of the steps of the method 3900 are performedlocally at the site where the patient is being treated and during asingle patient visit, referred to herein as “chair side manufacturing.”Chair side manufacturing can involve, for example, scanning thepatient's teeth, automatically generating a treatment plan withtreatment stages, and immediately fabricating one or more orthodonticappliance(s) to treat the patient using a chair side direct fabricationmachine, all at the treating professional's office during a singleappointment. In embodiments where a series of appliances are used totreat the patient, the first appliance may be produced chair side forimmediate delivery to the patient, with the remaining appliancesproduced separately (e.g., off site at a lab or central manufacturingfacility) and delivered at a later time (e.g., at a follow upappointment, mailed to the patient). Alternatively, the methods hereincan accommodate production and immediate delivery of the entire seriesof appliances on site during a single visit. Chair side manufacturingcan thus improve the convenience and speed of the treatment procedure byallowing the patient to immediately begin treatment at thepractitioner's office, rather than having to wait for fabrication anddelivery of the appliances at a later date. Additionally, chair sidemanufacturing can provide improved flexibility and efficiency oforthodontic treatment. For instance, in some embodiments, the patient isre-scanned at each appointment to determine the actual positions of theteeth, and the treatment plan is updated accordingly. Subsequently, newappliances can be immediately produced and delivered chair side toaccommodate any changes to or deviations from the treatment plan.

FIG. 40 is a simplified block diagram of a data processing system 4000that may be used in executing methods and processes described herein.The data processing system 4000 typically includes at least oneprocessor 4002 that communicates with one or more peripheral devices viabus subsystem 4004. These peripheral devices typically include a storagesubsystem 4006 (memory subsystem 4008 and file storage subsystem 4014),a set of user interface input and output devices 4018, and an interfaceto outside networks 4016. This interface is shown schematically as“Network Interface” block 4016, and is coupled to correspondinginterface devices in other data processing systems via communicationnetwork interface 4024. Data processing system 4000 can include, forexample, one or more computers, such as a personal computer,workstation, mainframe, laptop, and the like.

The user interface input devices 4018 are not limited to any particulardevice, and can typically include, for example, a keyboard, pointingdevice, mouse, scanner, interactive displays, touchpad, joysticks, etc.Similarly, various user interface output devices can be employed in asystem of the invention, and can include, for example, one or more of aprinter, display (e.g., visual, non-visual) system/subsystem,controller, projection device, audio output, and the like.

Storage subsystem 4006 maintains the basic required programming,including computer readable media having instructions (e.g., operatinginstructions, etc.), and data constructs. The program modules discussedherein are typically stored in storage subsystem 4006. Storage subsystem4006 typically includes memory subsystem 4008 and file storage subsystem4014. Memory subsystem 4008 typically includes a number of memories(e.g., RAM 4010, ROM 4012, etc.) including computer readable memory forstorage of fixed instructions, instructions and data during programexecution, basic input/output system, etc. File storage subsystem 4014provides persistent (non-volatile) storage for program and data files,and can include one or more removable or fixed drives or media, harddisk, floppy disk, CD-ROM, DVD, optical drives, and the like. One ormore of the storage systems, drives, etc may be located at a remotelocation, such coupled via a server on a network or via theinternet/World Wide Web. In this context, the term “bus subsystem” isused generically so as to include any mechanism for letting the variouscomponents and subsystems communicate with each other as intended andcan include a variety of suitable components/systems that would be knownor recognized as suitable for use therein. It will be recognized thatvarious components of the system can be, but need not necessarily be atthe same physical location, but could be connected via variouslocal-area or wide-area network media, transmission systems, etc.

Scanner 4020 includes any means for obtaining a digital representation(e.g., images, surface topography data, etc.) of a patient's teeth(e.g., by scanning physical models of the teeth such as casts 4021, byscanning impressions taken of the teeth, or by directly scanning theintraoral cavity), which can be obtained either from the patient or fromtreating professional, such as an orthodontist, and includes means ofproviding the digital representation to data processing system 4000 forfurther processing. Scanner 4020 may be located at a location remotewith respect to other components of the system and can communicate imagedata and/or information to data processing system 4000, for example, viaa network interface 4024. Fabrication system 4022 fabricates appliances4023 based on a treatment plan, including data set information receivedfrom data processing system 4000. Fabrication machine 4022 can, forexample, be located at a remote location and receive data setinformation from data processing system 4000 via network interface 4024.

The data processing aspects of the methods described herein can beimplemented in digital electronic circuitry, or in computer hardware,firmware, software, or suitable combinations thereof. Data processingapparatus can be implemented in a computer program product tangiblyembodied in a machine-readable storage device for execution by aprogrammable processor. Data processing steps can be performed by aprogrammable processor executing program instructions to performfunctions by operating on input data and generating output. The dataprocessing aspects can be implemented in one or more computer programsthat are executable on a programmable system, the system including oneor more programmable processors operably coupled to a data storagesystem. Generally, a processor will receive instructions and data from aread-only memory and/or a random access memory. Storage devices suitablefor tangibly embodying computer program instructions and data includeall forms of nonvolatile memory, such as: semiconductor memory devices,such as EPROM, EEPROM, and flash memory devices; magnetic disks such asinternal hard disks and removable disks; magneto-optical disks; andCD-ROM disks.

While preferred embodiments of the present invention have been shown anddescribed herein, it will be obvious to those skilled in the art thatsuch embodiments are provided by way of example only. Numerousvariations, changes, and substitutions will now occur to those skilledin the art without departing from the invention. It should be understoodthat various alternatives to the embodiments of the invention describedherein may be employed in practicing the invention. Numerous differentcombinations of embodiments described herein are possible, and suchcombinations are considered part of the present disclosure. In addition,all features discussed in connection with any one embodiment herein canbe readily adapted for use in other embodiments herein. It is intendedthat the following claims define the scope of the invention and thatmethods and structures within the scope of these claims and theirequivalents be covered thereby.

1. (canceled)
 2. A computer-implemented method for digitally designing aplurality of aligners, the computer-implemented method comprising:receiving an intraoral scan of the patient's teeth, wherein theintraoral scan captures an initial arrangement of the patient's teeth;generating a three-dimensional (3D) dental model of the patient's teethusing the intraoral scan; identifying a target arrangement for thepatient's teeth using a treatment plan applied to the 3D dental model;identifying a movement path to move the patient's teeth from the initialarrangement toward the target arrangement through a plurality ofintermediate arrangements in accordance with the treatment plan;identifying appliance geometries for a plurality of aligners toimplement the movement path; identifying one or more appliance featuresof at least one aligner of the plurality of aligners, wherein the one ormore appliance features include one or more feature regions having oneor more feature thicknesses; modifying an appliance geometry of the atleast one aligner to include the one or more feature thicknesses at theone or more feature regions; and instructing an additive manufacturingmachine to directly fabricate the plurality of aligners in alayer-by-layer fashion, including the at least one aligner having theappliance features with the one or more feature thicknesses at the oneor more feature regions.
 3. The computer-implemented method of claim 2,wherein the one or more appliance features comprise one or more forceapplication structures shaped to apply one or more forces to thepatient's teeth within the one or more feature regions.
 4. Thecomputer-implemented method of claim 2, wherein the one or moreappliance features comprise one or more force application structuresshaped to extend inward from an interior surface of a shell of the atleast one aligner toward a received tooth to define a contact point forapplication of force to the received tooth.
 5. The computer-implementedmethod of claim 2, wherein the one or more appliance features compriseone or more force application structures formed on a buccal surface of ashell of the at least one aligner, a lingual surface of the shell, anocclusal surface of the shell, or a combination thereof.
 6. Thecomputer-implemented method of claim 2, wherein the one or moreappliance features comprise one or more force application structuresshaped to control one or more of a tipping or a torque on a tooth of thepatient's teeth.
 7. The computer-implemented method of claim 2, whereinthe one or more appliance features comprise one or more forceapplication structures shaped to control movement of one or more rootsof the patient's teeth.
 8. The computer-implemented method of claim 2,wherein the one or more appliance features comprise one or more forceapplication structures shaped to control tooth rotation of one or moreteeth of the patient's teeth.
 9. The computer-implemented method ofclaim 2, wherein the one or more appliance features comprise one or morehandle structures on the at least one aligner.
 10. Thecomputer-implemented method of claim 2, wherein the one or moreappliance features comprise one or more gingival edges on the at leastone aligner.
 11. The computer-implemented method of claim 2, wherein theone or more appliance features comprise one or more thickened ribs onthe at least one aligner.
 12. The computer-implemented method of claim2, wherein the one or more appliance features comprise a plurality ofthicker regions having a thickness greater than a thickness of aproximate region proximate to the one or more feature regions.
 13. Thecomputer-implemented method of claim 2, wherein the one or moreappliance features comprise one or more occlusal regions of the at leastone aligner.
 14. The computer-implemented method of claim 2, wherein theone or more appliance features comprise vertical regions on the at leastone aligner.
 15. The computer-implemented method of claim 2, wherein theone or more appliance features comprise a plurality of thinner regionshaving a thickness less than a thickness of a proximate region proximateto the one or more feature regions.
 16. The computer-implemented methodof claim 2, wherein the one or more appliance features comprise aplurality of force isolated segments.
 17. The computer-implementedmethod of claim 2, wherein the one or more appliance features comprise aplurality of force transfer features.
 18. The computer-implementedmethod of claim 2, wherein the one or more appliance features compriseone or more regions shaped to receive one or more elastics.
 19. Thecomputer-implemented method of claim 2, wherein the one or moreappliance features comprise one or more hooks shaped to receive one ormore elastics.
 20. The computer-implemented method of claim 2, whereinthe one or more appliance features comprise one or more variablethickness regions having a variable thickness therein.
 21. Thecomputer-implemented method of claim 2, wherein instructing the additivemanufacturing machine to directly fabricate the plurality of aligners ina layer-by-layer fashion comprises: instructing the additivemanufacturing machine to additively manufacture the one or more featureregions using first photopolymerization parameters; and instructing theadditive manufacturing machine to additively manufacture one or moreproximate regions proximate to the one or more feature regions usingsecond photopolymerization parameters different than the firstphotopolymerization parameters.
 22. The computer-implemented method ofclaim 2, wherein instructing the additive manufacturing machine todirectly fabricate the plurality of aligners in a layer-by-layer fashioncomprises: instructing the additive manufacturing machine to form theone or more feature regions using a first material; and instructing theadditive manufacturing machine to form one or more proximate regionsproximate to the one or more feature regions feature regions using asecond material different than the first material.
 23. Thecomputer-implemented method of claim 2, further comprising capturing theintraoral scan using an intraoral scanner.
 24. The computer-implementedmethod of claim 2, further comprising directly fabricating the pluralityof aligners in the layer-by-layer fashion using the additivemanufacturing machine.
 25. The computer-implemented method of claim 2,further comprising exporting into an additive manufacturing file arepresentation of the at least one aligner having the modified appliancegeometry including the one or more feature thicknesses at the one ormore feature regions.
 26. The computer-implemented method of claim 25,wherein the additive manufacturing file comprises a stereolithographyfile.
 27. A system comprising: one or more processors; memory includingcomputer program instructions that, when executed by the one or moreprocessors, cause the system to perform a computer-implemented methodcomprising: receiving an intraoral scan of the patient's teeth, whereinthe intraoral scan captures an initial arrangement of the patient'steeth; generating a three-dimensional (3D) dental model of the patient'steeth using the intraoral scan; identifying a target arrangement for thepatient's teeth using a treatment plan applied to the 3D dental model;identifying a movement path to move the patient's teeth from the initialarrangement toward the target arrangement through a plurality ofintermediate arrangements in accordance with the treatment plan;identifying appliance geometries for a plurality of aligners toimplement the movement path; identifying one or more appliance featuresof at least one aligner of the plurality of aligners, wherein theappliance features include one or more feature regions having one ormore feature thicknesses; modifying an appliance geometry of the atleast one aligner to include the one or more feature thicknesses at theone or more feature regions; exporting into an additive manufacturingfile a representation of the at least one aligner having the modifiedappliance geometry including the one or more feature thicknesses at theone or more feature regions; and instructing an additive manufacturingmachine to directly fabricate the plurality of aligners in alayer-by-layer fashion, including the at least one aligner having theappliance features with the one or more feature thicknesses at the oneor more feature regions.
 28. The system of claim 27, further comprisingan intraoral scanner operable to capture the intraoral scan.
 29. Thesystem of claim 27, further comprising the additive manufacturingmachine operable to directly fabricate the plurality of aligners in thelayer-by-layer fashion.